Fix relative title key dropping namespace

 * If a title is relative, the key will already contain the namespace
   from env.page.name, which should be dropped. This didn't account for
   purely hash links, didn't appear to be using the right keyPart and
   wasn't normalizing it to find the namespace id.

 * Not sure the changes in 729c3decefad74e315a985bd2fd196ee23127ee6 ever
   worked as intended.

 * TODO: Look into why setPageSrcInfo updates a few page properties as
   metadata and where we're using those. The changes here from
   page.meta.ns > page.ns is because meta isn't set in the test suite.

Bug: 67451
Change-Id: I6714b7a62b18c74a7f845d17e98ae03dc520a983
Merge "Fix relative title key dropping namespace"