Sync oslo-incubator code to latest

Currently, gettextutils has graduated from oslo-incubator, so we
need to port to new library oslo.i18n, this sync is the first move
to do that.

Sync to latest:
    commit 62339865b57eeaa3212ce61427feb19a8c0b0c0e
    Add more to the release notes
    Change-Id: Ifad658f532b5d549144008170bfe2e4181038ddf

Change-Id: I3a2432ba2960c74db614e017e29bd95c560176f6
Partial-Bug: #1389546
Merge "Sync oslo-incubator code to latest"