bots: Refactor bots to use send_reply.

The send_reply function makes it easier for bots
to send messages. This commit updates all bots to
make use of this function, when possible.

contrib_bots/bots/giphy/giphy.py

@@ -35,20 +35,7 @@ class GiphyHandler(object):
 
     def handle_message(self, message, client, state_handler):
         bot_response = get_bot_giphy_response(message, client)
-
-        if message['type'] == 'private':
-            client.send_message(dict(
-                type='private',
-                to=message['sender_email'],
-                content=bot_response,
-            ))
-        else:
-            client.send_message(dict(
-                type='stream',
-                to=message['display_recipient'],
-                subject=message['subject'],
-                content=bot_response,
-            ))
+        client.send_reply(message, bot_response)
 
 
 class GiphyNoResultException(Exception):