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.
Propagate remote process environment.

* net/tramp-sh.el (tramp-sh-handle-start-file-process)
(tramp-sh-handle-process-file): Propagate `process-environment'.

* vc/vc-hg.el (vc-hg-state): No special handling for remote files;
Tramp propagates environment variables now.
Merge branch 'master' of git.sv.gnu.org:/srv/git/emacs