(Bug 19487) Fix predefined property annotation for file upload

Even though it is called Semantic-Media-Wiki, media 'file' upload annotation
has been broken since 2009.

As for the original Bug 19487, predefined properties are now correctly
updated whenever a new upload takes place and moreover MEDIA and MIME are
now set automatically (if configuration enables it).

Change-Id: Ie184e9d796ef8aac0ab579f84a1b8c81032347c0
Merge pull request #164 from SemanticMediaWiki/fileupload

(Bug 19487) Fix predefined property annotation for file upload