Add .mo files to MANIFEST.in

Translations .mo files created with compile_catalog should
be included in the build if they exist.

Additionally, .pot files have been removed from source git in
https://review.openstack.org/307589 so they can be ignored in
MANIFEST.in.

Closes-Bug: 1583611

Change-Id: Ia0c87360d34936d432eceb22210f03f8592c6fec

MANIFEST.in

@@ -17,5 +17,5 @@ graft doc
 graft keystone/tests
 graft tools
 graft examples
-recursive-include keystone *.json *.xml *.cfg *.pem README *.po *.pot *.sql
+recursive-include keystone *.json *.xml *.cfg *.pem README *.po *.mo *.sql
 global-exclude *.pyc *.sdx *.log *.db *.swp keystone/tests/tmp/*