SQL fix for get_roles_for_user_and_project user=group ID

When there was a role assigned to a group with the same ID as a
user, the SQL assignment backend would incorrectly return the
assignment to the group when requesting roles for the user via
the get_roles_for_user_and_project method.

With this change, assignments to a group with the same ID are not
returned for the user when calling get_roles_for_user_and_project.

Change-Id: Id3d6f66c995e65e37d909359420d71ecdde86b69
Partial-Bug: #1309228
Remove all mostly untranslated PO files

We now only import PO files that are at least 75 % translated,
so we can delete now all other PO files. The patch only
removes the mostly untranslated files. Once a file becomes mostly
translated, the bot will import it again.

This patch leaves the mostly translated languages Australian English,
US English and Brazilian Portuguese in.

Change-Id: Ib26bc5147f0dc3d49f9b97bc0b8682a8c62c81b8
Closes-Bug: #1317794
Merge "Remove all mostly untranslated PO files"