Problem:- Gtid are not transferred in Galera Cluster.

Solution:- We need to transfer gtid in the case on either when cluster is
slave/master in async replication. In normal Gtid replication gtid are generated on
recieving node itself and it is always on sync with other nodes. Because galera keeps
node in sync , So all nodes get same no of event groups. So the issue arises when
say galera is slave in async replication.
A
|    (Async replication)
D <-> E <-> F  {Galera replication}
So what should happen is that all node should apply the master gtid but this does
node happen, becuase node E, F does not recieve gtid from D in write set , So what E(or F)
does is that it applies wsrep_gtid_domain_id, D server-id , E gtid next seq no. This
generated gtid does not always work when say A has different domain id.

So In this commit, on galera node when we see that this event is recieved from master
we simply write Gtid_Log_Event in write_set and send it to other nodes.