[1.2.X] Fixed #14910 -- Clarified the order of precedence of loading...

[1.2.X] Fixed #14910 -- Clarified the order of precedence of loading translation catalogues. Thanks, vanschelven.

Backport from trunk (r14998).

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15002 bcc190cf-cafb-0310-a4f2-bffc1f526a37