Merge branch 'maint'

Merge branch 'maint'

* maint:
  Update release notes for 1.6.0.3
  checkout: Do not show local changes when in quiet mode
  for-each-ref: Fix --format=%(subject) for log message without newlines
  git-stash.sh: don't default to refs/stash if invalid ref supplied
  maint: check return of split_cmdline to avoid bad config strings