res_rtp_asterisk: Set correct raddr port on RTCP srflx candidates.

RTCP ICE candidates use a base address derived from the RTP
candidate. The port on the base address was not being updated to
the RTCP port.

This change sets the base port to the RTCP port and all is well.

ASTERISK-29433

Change-Id: Ide2d2115b307bfd3c2dfbc4d187515d724519040

res/res_rtp_asterisk.c

@@ -3687,6 +3687,7 @@ static void rtp_add_candidates_to_ice(struct ast_rtp_instance *instance, struct
 			ao2_iterator_destroy(&i);
 
 			if (srflx && baseset) {
+				pj_sockaddr_set_port(&base, port);
 				ast_rtp_ice_add_cand(instance, rtp, component, transport,
 					PJ_ICE_CAND_TYPE_SRFLX, 65535, &ext, &base, &base,
 					pj_sockaddr_get_len(&ext));