Fix returnto in p-personal generated by JS check

When the JS check replaces the #p-personal bar, the "returnto" in the
generated logout link is pointing to Special:CentralAutoLogin/setCookies
rather than the page the user is actually on.

Change-Id: I0fbc798cb5c81fc356edfbc8e4e7e973c4ff5ab7
Merge "Fix returnto in p-personal generated by JS check"