Set the correct special page headers so that "What links here" and "Page
info" won't show up on the toolbox when you're viewing these special
pages.

Also fixed a bug with the "Use social userpage/Use wiki userpage" button
label message in UserProfile/UserProfilePage.php. Previously it would
display (at least initially) "Use social userpage" even when you were
already using it (in which case the label should've prompted you to "Use
wiki userpage" instead).

Change-Id: I0269d5ed560f233bd0736ac710d00aaaab5c71f2