replace dict.iteritems() with six.iteritems(dict)

According to https://wiki.openstack.org/wiki/Python3 dict.iteritems()
should be replaced with six.iteritems(dict).

Added six >= 1.6.0 as new requirement.

Change-Id: Ie8a3eacc00dd9248ee80956b3e72f0e80655b1f1

gerritbot/bot.py

@@ -52,6 +52,7 @@ import irc.bot
 import logging.config
 import os
 import re
+import six
 import ssl
 import sys
 import threading
@@ -281,7 +282,7 @@ class ChannelConfig(object):
         self.projects = {}
         self.events = {}
         self.branches = {}
-        for channel, val in self.data.iteritems():
+        for channel, val in six.iteritems(self.data):
             for event in val['events']:
                 event_set = self.events.get(event, set())
                 event_set.add(channel)

requirements.txt

@@ -5,3 +5,4 @@ gerritlib
 irc
 pyyaml
 python-daemon
+six>=1.6.0