Do not include file redirects in Special:Wantedfiles

If you look at [[Special:WantedFiles]] on commons, its full
of file redirects, making the page kind of useless. This makes
the query much more complex, but at least the page will be useful.

The page will still be useless on non-commons projects due to
foreign files being listed as missing.

Change-Id: I115fdaa3b67bee81ba0a715ebb427bb35cf0f67e
Merge "Do not include file redirects in Special:Wantedfiles"