Merge branch 'sb/quiet-porcelains'

* sb/quiet-porcelains:
  stash: teach quiet option
  am, rebase: teach quiet option
  submodule, repack: migrate to git-sh-setup's say()
  git-sh-setup: introduce say() for quiet options
  am: suppress apply errors when using 3-way
  t4150: test applying with a newline in subject

diff --cc git-rebase.sh
Simple merge

diff --cc git-submodule.sh
Simple merge