revert: always show relative path to .orig backup

This helps make some future patches easier when I replace origpath()
by another function that works with repo-relative paths (origpath()
works with cwd-relative paths).

Always showing a relative path seems a little more user-friendly and
is more consistent between configured ui.origbackuppath and not. OTOH,
it's annoying if ui.origbackuppath is far outside the repo. This is
just --verbose output, so I don't think it's worth spending much time
on (I've already wasted too many hours on it).

Differential Revision: https://phab.mercurial-scm.org/D5871

mercurial/cmdutil.py

@@ -3018,8 +3018,9 b' def revert(ui, repo, ctx, parents, *pats'
                             tobackup.add(abs)
                         elif (backup <= dobackup or wctx[abs].cmp(ctx[abs])):
                             bakname = scmutil.origpath(ui, repo, rel)
+                            relbakname = os.path.relpath(bakname)
                             ui.note(_('saving current version of %s as %s\n') %
-                                    (rel, bakname))
+                                    (rel, relbakname))
                             if not opts.get('dry_run'):
                                 if interactive:
                                     util.copyfile(target, bakname)

tests/test-largefiles-misc.t

@@ -578,7 +578,7 b' Test orig files go where we want them'
   $ echo moremore >> anotherlarge
   $ hg revert anotherlarge -v --config 'ui.origbackuppath=.hg/origbackups'
   creating directory: $TESTTMP/addrm2/.hg/origbackups/.hglf/sub
-  saving current version of ../.hglf/sub/anotherlarge as $TESTTMP/addrm2/.hg/origbackups/.hglf/sub/anotherlarge
+  saving current version of ../.hglf/sub/anotherlarge as ../.hg/origbackups/.hglf/sub/anotherlarge
   reverting ../.hglf/sub/anotherlarge
   creating directory: $TESTTMP/addrm2/.hg/origbackups/sub
   found 90c622cf65cebe75c5842f9136c459333faf392e in store

tests/test-revert.t

@@ -92,7 +92,7 b' Test creation of backup (.orig) file in '
   $ echo z > e
   $ hg revert --all -v --config 'ui.origbackuppath=.hg/origbackups'
   creating directory: $TESTTMP/repo/.hg/origbackups
-  saving current version of e as $TESTTMP/repo/.hg/origbackups/e
+  saving current version of e as .hg/origbackups/e
   reverting e
   $ rm -rf .hg/origbackups