Sets subscribed type for outgoing MWI subscriptions so correct Event header is used.

git-svn-id: https://origsvn.digium.com/svn/asterisk/branches/1.8@286834 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -11522,7 +11522,9 @@ static int __sip_subscribe_mwi_do(struct sip_subscription_mwi *mwi)
 	
 	/* Associate the call with us */
 	mwi->call->mwi = ASTOBJ_REF(mwi);
-	
+
+	mwi->call->subscribed = MWI_NOTIFICATION;
+
 	/* Actually send the packet */
 	transmit_invite(mwi->call, SIP_SUBSCRIBE, 0, 2, NULL);