Fix deprecation warnings due to invalid escape sequences.

Author: tirkarthi

pyclowder/extractors.py

@@ -143,7 +143,7 @@ def start(self):
                     for key, value in self.extractor_info['process'].items():
                         for mt in value:
                             # Replace trailing '*' with '#'
-                            mt = re.sub('(\*$)', '#', mt)
+                            mt = re.sub(r'(\*$)', '#', mt)
                             if mt.find('*') > -1:
                                 logger.error("Invalid '*' found in rabbitmq_key: %s" % mt)
                             else: