More movement of master-related code to vc-filewise.el.

Goes with my 2014-11-22 lisp/ChangeLog entry.
Revert "More movement of master-related code to vc-filewise.el."

Must unbreak the build.  Which is way too complicated...
Unbreak the build.

I don't really understand why this reversion works, but it will do until I can
actually comprehend the bizarre hairball that is Emacs bootstrapping.