Fix file summary message
The summary is wikitext, mw.msg parses limited wikitext into HTML, which not
only isn't the correct behaviour, but limits what wikitext can be used in the
summary; primarily templates.
Change-Id: I5dc384ddba4270c1f71005401e1bae073cd2b627
(cherry picked from commit ead03a7a42a3a369c37513f8220ed3c10a958d0f)