PJSIP: Allow use of 'inactive' streams for hold

This allows use of the 'inactive' stream direction identifier to be
used for hold where 'sendonly' is normally used. Some Seimens phones
use 'inactive' and this change allows music on hold to operate
properly.

Review: https://reviewboard.asterisk.org/r/4252/
Reported by: Steve Pitts
........

Merged revisions 429432 from http://svn.asterisk.org/svn/asterisk/branches/12
........

Merged revisions 429433 from http://svn.asterisk.org/svn/asterisk/branches/13


git-svn-id: https://origsvn.digium.com/svn/asterisk/certified/branches/13.1@429865 65c4cc65-6c06-0410-ace0-fbb531ad65f3

res/res_pjsip_sdp_rtp.c

@@ -1187,7 +1187,8 @@ static int apply_negotiated_sdp_stream(struct ast_sip_session *session, struct a
 
 	if (ast_sockaddr_isnull(addrs) ||
 		ast_sockaddr_is_any(addrs) ||
-		pjmedia_sdp_media_find_attr2(remote_stream, "sendonly", NULL)) {
+		pjmedia_sdp_media_find_attr2(remote_stream, "sendonly", NULL) ||
+		pjmedia_sdp_media_find_attr2(remote_stream, "inactive", NULL)) {
 		if (!session_media->held) {
 			/* The remote side has put us on hold */
 			ast_queue_hold(session->channel, session->endpoint->mohsuggest);