Some variables and templates variables that should be translatable
weren't marked as such.
Fixes bug #1180316
Note the change in horizon/templates/horizon/common/_quota_summary.html
is not backported in this commit to keep the existing translations work.
Change-Id: I90baf19c4bea09c126f8ed225777037194f5331f
(cherry picked from commit acfb83d5d5)