Made generic the logstash serialization function

Author: alexcos78

caso/messenger/logstash.py

@@ -70,7 +70,7 @@ def push(self, records):
         try:
           for record in records:
         #serialization of record
-              rec=record.logstash_message()
+              rec=record.serialization_message()
         #cASO timestamp added to each record
               rec['caso-timestamp']=ct
         #Send the record to LS

caso/record.py

@@ -49,7 +49,7 @@ def ssm_message(self):
         raise NotImplementedError("Method not implemented")
 
 
-    def logstash_message(self):
+    def serialization_message(self):
         """Render record as the expected logstash message."""
         opts = {
             "by_alias": True,