get normalised parameters should not take into account oauth_ params

Author: gregtap

oauth2/__init__.py

@@ -359,7 +359,10 @@ def get_normalized_parameters(self):
 
         # Include any query string parameters from the provided URL
         query = urlparse.urlparse(self.url)[4]
-        items.extend(self._split_url_string(query).items())
+        
+        url_items = self._split_url_string(query).items()
+        non_oauth_url_items = list([(k, v) for k, v in url_items  if not k.startswith('oauth_')])
+        items.extend(non_oauth_url_items)
 
         encoded_str = urllib.urlencode(sorted(items))
         # Encode signature parameters per Oauth Core 1.0 protocol