res_pjsip_sdp_rtp.c: Fix cut-n-paste error

We were inadvertenly referencing the cos_video option to determine if we
should set the tos_audio and cos_audio value on the RTP instance.

Change-Id: Ia7964f486801d39dc6f5dae570baff079e1595b0

res/res_pjsip_sdp_rtp.c

@@ -217,7 +217,7 @@ static int create_rtp(struct ast_sip_session *session, struct ast_sip_session_me
 	}
 
 	if (!strcmp(session_media->stream_type, STR_AUDIO) &&
-			(session->endpoint->media.tos_audio || session->endpoint->media.cos_video)) {
+			(session->endpoint->media.tos_audio || session->endpoint->media.cos_audio)) {
 		ast_rtp_instance_set_qos(session_media->rtp, session->endpoint->media.tos_audio,
 				session->endpoint->media.cos_audio, "SIP RTP Audio");
 	} else if (!strcmp(session_media->stream_type, STR_VIDEO) &&