Update rate limit response text and log message

Use Cisco Spark’s provided response code description, and shorten the
log message given the updated response text.

Author: cmlccie

ciscosparkapi/exceptions.py

@@ -33,7 +33,10 @@
     409: "The request could not be processed because it conflicts with some "
          "established rule of the system. For example, a person may not be "
          "added to a room more than once.",
-    429: "Rate limit exceeded.",
+    429: "Too many requests have been sent in a given amount of time and the "
+         "request has been rate limited. A Retry-After header should be "
+         "present that specifies how many seconds you need to wait before a "
+         "successful request can be made.",
     500: "Something went wrong on the server.",
     503: "Server is overloaded with requests. Try again later."
 }

ciscosparkapi/restsession.py

@@ -267,8 +267,8 @@ def request(self, method, relative_url, erc, **kwargs):
                 if e.response_code == RATE_LIMIT_EXCEEDED_RESPONSE_CODE \
                         and response.headers.get('Retry-After'):
 
-                    logger.debug("Received a [{}] {} response."
-                                 "".format(e.response_code, e.response_text))
+                    logger.debug("Received a [%s] rate limit response. "
+                                 "Attempting to retry.", e.response_code)
 
                     rate_limit_wait = response.headers['Retry-After']