Make UserNotLoggedIn redirect to login page

For pages like Special:Watchlist that throw
a UserNotLoggedIn exception when the user is
anonymous, this patch makes the page redirect
to the login page automatically.

This is instead
of the current behavior of showing a link to
the login page that the user must click.

(Also, Special:Userlogin has existing functionality
that will redirect the user back once they are
logged in.)

Bug: 15484
Change-Id: Idd9325374cb5dc13c4c057f45f88a33bdff523a9
Merge "Make UserNotLoggedIn redirect to login page"