don't add rtpmap or mid attributes for deleted/silenced streams

fixes #686

Change-Id: Ie9a155072a8b6acb8edcf59a5dd164f78a503616
(cherry picked from commit 415af36ae6)

daemon/sdp.c

@@ -2060,6 +2060,9 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 
 			copy_up_to_end_of(chop, &sdp_media->s);
 
+			if (!sdp_media->port_num || !ps->selected_sfd)
+				goto next;
+
 			insert_codec_parameters(chop, call_media);
 
 			ps_rtcp = NULL;
@@ -2071,9 +2074,6 @@ int sdp_replace(struct sdp_chopper *chop, GQueue *sessions, struct call_monologu
 				assert(j->data == ps_rtcp);
 			}
 
-			if (!sdp_media->port_num || !ps->selected_sfd)
-				goto next;
-
 			if (MEDIA_ARESET2(call_media, SEND, RECV))
 				chopper_append_c(chop, "a=sendrecv\r\n");
 			else if (MEDIA_ISSET(call_media, SEND))