Call loadFromRow() as needed in Title::moveToInternal.

* Follows up 61c0064de538c3b1ea61470eadd88fab87d3513e,
  which was missing a load call to fully fix the bug.
  Calling loadFromRow() forced the page to load as
  non-existing (which it should be).
* The redirect title was triggering a load from a slave in
  updateRevisionOn() and wrongly updating the destination page
  to point to the redirect revision and leaving the redirect
  page with page_latest=0;

Bug : 46397
Change-Id: Id6abe062a0266a790716df8c592911fd89b83223