Seeing the same issue in 2.20-55~icehouse 

Setup
=====
Login to 10.84.34.6(root/c0ntrail123)
Then login to 192.168.0.97(single-node setup)

Traceback-logs
=============
2015-06-18 00:56:49.403 2141 AUDIT nova.compute.claims [req-19cf4c93-2ce2-4a80-8782-916627977825 6ccc4bf14a7642eb9db11a1e63e696f3 ef6912a479b44df3824914f8668ba70b] [instance: 9a52be1e-5fdc-4980-b773-a8b3d9ae676b] Claim successful
2015-06-18 00:56:49.841 2141 ERROR nova.compute.manager [-] Instance failed network setup after 1 attempt(s)
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager Traceback (most recent call last):
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1530, in _allocate_network_async
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager     dhcp_options=dhcp_options)
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager   File "/usr/lib/python2.7/dist-packages/nova/network/neutronv2/api.py", line 241, in allocate_for_instance
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager     raise exception.PortInUse(port_id=port_id)
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager PortInUse: Port 3a47c037-77c2-46e8-9cb0-833fdfb2880d is still in use.
2015-06-18 00:56:49.841 2141 TRACE nova.compute.manager
2015-06-18 00:56:50.347 2141 INFO nova.virt.libvirt.driver [req-e6cee510-bf62-4492-8ab7-473a4535dcab 0688e1f4f3a04ed7a0d9e26d1057391e ef6912a479b44df3824914f8668ba70b] [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb] Creating image
2015-06-18 00:56:50.500 2141 INFO nova.virt.libvirt.driver [req-19cf4c93-2ce2-4a80-8782-916627977825 6ccc4bf14a7642eb9db11a1e63e696f3 ef6912a479b44df3824914f8668ba70b] [instance: 9a52be1e-5fdc-4980-b773-a8b3d9ae676b] Creating image
2015-06-18 00:56:50.616 2141 ERROR nova.compute.manager [req-e6cee510-bf62-4492-8ab7-473a4535dcab 0688e1f4f3a04ed7a0d9e26d1057391e ef6912a479b44df3824914f8668ba70b] [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb] Instance failed to spawn
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb] Traceback (most recent call last):
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1740, in _spawn
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     block_device_info)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 2290, in spawn
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     admin_pass=admin_password)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 2760, in _create_image
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     instance, network_info, admin_pass, files, suffix)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/virt/libvirt/driver.py", line 2559, in _inject_data
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     net = netutils.get_injected_network_template(network_info)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/virt/netutils.py", line 71, in get_injected_network_template
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     if not (network_info and template):
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/network/model.py", line 424, in __len__
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     return self._sync_wrapper(fn, *args, **kwargs)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/network/model.py", line 411, in _sync_wrapper
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     self.wait()
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/network/model.py", line 449, in wait
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     self[:] = self._gt.wait()
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/eventlet/greenthread.py", line 168, in wait
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     return self._exit_event.wait()
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/eventlet/event.py", line 120, in wait
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     current.throw(*self._exc)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/eventlet/greenthread.py", line 194, in main
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     result = function(*args, **kwargs)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/compute/manager.py", line 1530, in _allocate_network_async
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     dhcp_options=dhcp_options)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]   File "/usr/lib/python2.7/dist-packages/nova/network/neutronv2/api.py", line 241, in allocate_for_instance
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb]     raise exception.PortInUse(port_id=port_id)
2015-06-18 00:56:50.616 2141 TRACE nova.compute.manager [instance: 555f0d28-d55d-4d57-9466-1563f5a0aafb] PortInUse: Port 3a47c037-77c2-46e8-9cb0-833fdfb2880d is still in use.

Keeping the setup as is.