Merge branch 'ld/push-porcelain'

* ld/push-porcelain:
  t5516: Use test_cmp when appropriate
  git-push: add tests for git push --porcelain
  git-push: make git push --porcelain print "Done"
  git-push: send "To <remoteurl>" messages to the standard output in --porcelain mode
  git-push: fix an advice message so it goes to stderr

Conflicts:
	transport.c