Fix Jenkins translation jobs

The jobs heat-propose-translation-update and
heat-upstream-translation-update do not update from
transifex since our po files contain duplicate entries where
obsolete entries duplicate normal entries.

Remove all obsolete entries to fix the jobs.

Change-Id: I2071e3a792d107840449bbfe39e3a540ea1b626f
Closes-Bug: #1299349
Merge "Fix Jenkins translation jobs"