use_nova_chains fails due to a missing flag

[Vish Ishaya]

Trying to use nova chains fails with the following traceback:

(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/nova/network/manager.py", line 124, in init_host
(nova.root): TRACE: self.driver.init_host()
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/nova/network/linux_net.py", line 76, in init_host
(nova.root): TRACE: _execute("sudo iptables -D %s -j nova_input" % FLAGS.input_chain,
(nova.root): TRACE: File "/usr/lib/pymodules/python2.6/nova/flags.py", line 139, in __getattr__
(nova.root): TRACE: val = gflags.FlagValues.__getattr__(self, name)
(nova.root): TRACE: File "/usr/lib/python2.6/dist-packages/gflags.py", line 810, in __getattr__
(nova.root): TRACE: raise AttributeError(name)
(nova.root): TRACE: AttributeError: input_chain

Looks like a flag got missed.