Sync gettextutils from oslo

Some Messages, like those from Invalid exceptions, use a Message within
a Message, and we were only translating the base Message but not the
Message substitution within.

Fixes bug: #1221808

Change-Id: Ic3119df23a090cfaa160c1461e955f0af55fe1cf
Consider downloading a valid status for CinderVolume

"downloading" should be considered a in-progress state while creating a volume
from an image. Because Cinder will first create a volume with specified size
and set its status to downloading, then start fetching the image from glance
and copying it to the volume.

Fixes bug #1222676

Change-Id: I573440f3184c3d47df0d7e78146b0ed030606d86
Merge "Sync gettextutils from oslo"
Merge "Consider downloading a valid status for CinderVolume"