Avoid raising meaningless exception of AttributeError

[Jie Li]

2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent Traceback (most recent call last):
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 138, in _dispatch_and_reply
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent incoming.message))
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent File "/usr/lib/python2.7/site-packages/oslo_messaging/rpc/dispatcher.py", line 185, in _dispatch
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent localcontext._clear_local_context()
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent File "/usr/lib/python2.7/site-packages/oslo_messaging/localcontext.py", line 85, in _clear_local_context
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent delattr(_STORE, _KEY)
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent
2016-03-22 01:13:25.947 TRACE neutron.agent.l3.agent AttributeError: _oslo_messaging_localcontext_48e241ba0b314590be30177a2e8af361

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/296932

[OpenStack Infra (hudson-openstack)]

Change abandoned by Mehdi Abaakouk (sileht) (<email address hidden>) on branch: master
Review: https://review.openstack.org/296932
Reason: this code is dead