Followup r94421 which, per CR, broke in non-English content languages because of...

Followup r94421 which, per CR, broke in non-English content languages because of key mismatches due to localized namespace names. Now ensuring all titles go through getPrefixedDBkey() before we compare them, so they're always normalized. This also ensures we don't get underscore vs. space confusion, which is something that the previous code did right by accident.