Using a redis backed elasticache, I'm getting a TypeError on this line (below). It looks like redis doesn't have a ConfigurationEndpoint. It does have the node endpoint port at `self.data['CacheNodes'][0]['Endpoint']['Port']`. (Assuming there is a cache node.)

      File "/Users/mjschultz/.ansible/tmp/ansible-1382205363.79-120642222168443/elasticache", line 403, in _requires_destroy_and_create
        'cache_port': self.data['ConfigurationEndpoint']['Port']
    TypeError: 'NoneType' object is not subscriptable