Merge branch 'tg/stash-push-fixup'

Recent enhancement to "git stash push" command to support pathspec
to allow only a subset of working tree changes to be stashed away
was found to be too chatty and exposed the internal implementation
detail (e.g. when it uses reset to match the index to HEAD before
doing other things, output from reset seeped out).  These, and
other chattyness has been fixed.

* tg/stash-push-fixup:
  stash: keep untracked files intact in stash -k
  stash: pass the pathspec argument to git reset
  stash: don't show internal implementation details