Quote message when reporting to Gerrit

If the message has double quotation marks, Gerrit will not be able
to parse it.  This applies shell quotes to the message before
sending it.

Change-Id: Ieda76b0f64346ab1388affead1a17630af61a5e6

zuul/driver/gerrit/gerritconnection.py

@@ -20,6 +20,7 @@ import threading
 import time
 from six.moves import queue as Queue
 from six.moves import urllib
+from six.moves import shlex_quote
 import paramiko
 import logging
 import pprint
@@ -614,7 +615,7 @@ class GerritConnection(BaseConnection):
     def review(self, project, change, message, action={}):
         cmd = 'gerrit review --project %s' % project
         if message:
-            cmd += ' --message "%s"' % message
+            cmd += ' --message %s' % shlex_quote(message)
         for key, val in action.items():
             if val is True:
                 cmd += ' --%s' % key