MT#55307 fix kamailio.acc existing index creation

* due to the fact that the initial script had been created as replicated
  and then renamed to _not_replicated, caused already deployed platforms on
  mr11.1, mr11.1.1, mr11.2, mr11.2.1 to have the index in both tables
  (because of the upgrade/ngcp-sync-db step on sp2) and a missing
  record in ngcp.db_schema for 'sp2' (because the script was named
  as replicated initially). To further address the issue, "CREATE INDEX"
  is now adjusted to "CREATE INDEX IF NOT EXISTS"

Change-Id: Ie1554bad9300da5ff711cfe53d1cc6c14f91793d
(cherry picked from commit d23bfb856c)

db_scripts/diff/15739_not_replicated.up

@@ -1,4 +1,4 @@
 SET sql_log_bin=0;
 USE kamailio;
 
-CREATE INDEX method_callid_idx ON acc (method,callid);
+CREATE INDEX IF NOT EXISTS method_callid_idx ON acc (method,callid);