Use `redis.from_url()` for greater compatibility.

This lets us keep the redis-py version requirement back at 2.4.13.

rq/scripts/__init__.py

@@ -47,7 +47,7 @@ def setup_default_arguments(args, settings):
 
 def setup_redis(args):
     if args.url is not None:
-        redis_conn = redis.Redis.from_url(args.url, db=args.db)
+        redis_conn = redis.from_url(args.url, db=args.db)
     else:
         redis_conn = redis.Redis(host=args.host, port=args.port, db=args.db,
             password=args.password)

setup.py

@@ -17,7 +17,7 @@ def get_version():
 
 
 def get_dependencies():
-    deps = ['redis >= 2.6.2', 'times']
+    deps = ['redis >= 2.4.13', 'times']
     deps += ['logbook']  # should be soft dependency?
     if sys.version_info < (2, 7) or \
             (sys.version_info >= (3, 0) and sys.version_info < (3, 1)):