Add send of pubcomp in 02-subpub-qos2 script

To keep the broker session working while launching several tests on
the same broker, the last packet of this transaction must be sent.

Signed-off-by: Jerome Malinge <gromgromm@yahoo.com>

test/broker/02-subpub-qos2.py

@@ -38,6 +38,7 @@ try:
 
     if mosq_test.expect_packet(sock, "publish2", publish_packet2):
         mosq_test.do_send_receive(sock, pubrec_packet2, pubrel_packet2, "pubrel2")
+        sock.send(pubcomp_packet2)
         # Broker side of flow complete so can quit here.
         rc = 0