Remove the log.isEnabledFor check as neutron log is not support yet

Remove the log.isEnabledFor in message.py as neutron does not sync the
oslo-incubate as nova's level, there is no isEnabledFor at this time in
neutron openstack.common.log.

Closes-Bug: #1373416
Change-Id: I1abda8017f55785e807d20dfa4d574c0a7016f60