Sync latest gettextutils from oslo-incubator

Fixes bug #1076285

Ensure translations for strings under nova.openstack.common are
translated using the 'nova' translation domain rather than the
non-existent 'openstack-common' translation domain.

Change-Id: I6aee3061cbffd3bf940f1881e8540cd996d0b12a
Merge "Sync latest gettextutils from oslo-incubator"