transport-helper: update ref status after push with export

Also add check_output from python 2.7.

Signed-off-by: Sverre Rabbelier <srabbelier@gmail.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

git-remote-testgit.py

@@ -147,11 +147,15 @@ def do_export(repo, args):
     sys.stdout.flush()
 
     update_local_repo(repo)
-    repo.importer.do_import(repo.gitdir)
+    changed = repo.importer.do_import(repo.gitdir)
 
     if not repo.local:
         repo.non_local.push(repo.gitdir)
 
+    for ref in changed:
+        print "ok %s" % ref
+    print
+
 
 COMMANDS = {
     'capabilities': do_capabilities,