Sync latest gettextutils from oslo-incubator

Pull some necessary changes from oslo for
implementing user-locale-api

partially implements bp user-locale-api

Change-Id: I6ac57e094e155760129e8df0e60bc7f2968aa439
Avoid performing extra query for fetching port security binding

Bug 1201957

Add a relationship performing eager load in Port and Network
models, thus preventing the 'extend' function from performing
an extra database query.
Also fixes a comment in securitygroups_db.py

Change-Id: If0f0277191884aab4dcb1ee36826df7f7d66a8fa
Merge "Sync latest gettextutils from oslo-incubator"
Merge "Avoid performing extra query for fetching port security binding"