MT#60120 use billing as default db when laoding from constants.yml

the "soap" sql user has no access to the "ngcp" database.
switch to "billing" as a default db to prevent an error when
loading credentials purely from constants.yml

Change-Id: Ia6afd27995784af52ac9beb7ba0d93b353d482d2
(cherry picked from commit 71ff87e49b)

lib/NGCP/BulkProcessor/Globals.pm

@@ -455,7 +455,7 @@ sub _update_constants_yml {
 
         $xa_host = $data->{database}->{central}->{dbhost};
         $xa_port = $data->{database}->{central}->{dbport};
-        $xa_databasename = 'ngcp';
+        $xa_databasename = 'billing';
         $xa_username = $data->{credentials}->{mysql}->{provisioning}->{u};
         $xa_password = $data->{credentials}->{mysql}->{provisioning}->{p};