Simplify catchall log handler attachment
Simplify catchall log handler attachment

We only need to attach it to the root logger,
since in our logging setup there is now no
non-propagating logger.

openstack/networking-bagpipe,openstack/networking-bagpipe-l2,stackforge/networking-bagpipe-l2,stackforge/networking-bagpipe-l2,openstack/networking-bagpipe,openstack/networking-bagpipe-l2