If no port is given but a server is, use that.

Only fall back to localhost if the URI is "redis_cache.cache://"

redis_cache/cache.py

@@ -33,7 +33,7 @@ class CacheClass(BaseCache):
             except (ValueError, TypeError):
                 port = 6379
         else:
-            host = 'localhost'
+            host = server or 'localhost'
             port = 6379
         self._cache = redis.Redis(host=host, port=port, db=db, password=password)