Updating docstring for WebPusher.send method

Removed duplicate description for :param reg_id:

Author: kamotos

pywebpush/__init__.py

@@ -158,8 +158,6 @@ def send(self, data, headers={}, ttl=0, gcm_key=None, reg_id=None):
         :param data: A serialized block of data (see encode() ).
         :param gcm_key: API key obtained from the Google Developer Console.
             Needed if endpoint is https://android.googleapis.com/gcm/send
-        :param reg_id: registration id of the recipient. If not provided,
-            it will be extracted from the endpoint.
         :param headers: A dictionary containing any additional HTTP headers.
         :param ttl: The Time To Live in seconds for this message if the
             recipient is not online. (Defaults to "0", which discards the