zulip_bots: Only cache storage.get(). Don't cache put().

zulip_bots/zulip_bots/bots/incrementor/incrementor.py

@@ -5,7 +5,6 @@ class IncrementorHandler(object):
     META = {
         'name': 'Incrementor',
         'description': 'Example bot to test the update_message() function.',
-        'uses_storage': True,
     }
 
     def usage(self):

zulip_bots/zulip_bots/bots/tictactoe/tictactoe.py

@@ -270,7 +270,6 @@ class ticTacToeHandler(object):
     META = {
         'name': 'TicTacToe',
         'description': 'Lets you play Tic-tac-toe against a computer.',
-        'uses_storage': True,
     }
 
     def usage(self):

zulip_bots/zulip_bots/bots/virtual_fs/virtual_fs.py

@@ -7,7 +7,6 @@ class VirtualFsHandler(object):
     META = {
         'name': 'VirtualFs',
         'description': 'Provides a simple, permanent file system to store and retrieve strings.',
-        'uses_storage': True,
     }
 
     def usage(self):