Changes:

1) Add initialization for trx->xid in InnoDB trx pool

2) Add server UUID in the XID of InnoDB SR transactions

3) Modify trx_recover_for_mysql_callback() so that recovered InnoDB SR
transactions are not made visible to MySQL as recovered XA transactions.

4) Modify how SR transactions are detected and the wsrep_is_sr flag is
set for InnoDB SR transactions.

include/wsrep/client_state.hpp

@@ -926,7 +926,16 @@ namespace wsrep
         {
             return transaction_;
         }
-
+#ifdef WITH_WSREP_SR_SPEEDUP
+        /**
+         * Return a reference to the transaction associated
+         * with the client state.
+         */
+        wsrep::transaction& transaction()
+        {
+            return transaction_;
+        }
+#endif /* WITH_WSREP_SR_SPEEDUP */
         const wsrep::ws_meta& toi_meta() const
         {
             return toi_meta_;