Don't send presencestate information if the state is invalid

Previously, presencestate information was sent whenever the state was not
NOT_SET. When r381594 actually returned INVALID presence state in all the
places it was supposed to, it caused chan_sip to start adding presence
state information to NOTIFY requests that it previously would not have
added. chan_sip shouldn't be adding presence state information when the
provider is in an invalid state; users can't set the state to invalid and
an invalid state always implies that the provider is in an error condition.

(issue AST-1084)
........

Merged revisions 381613 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@381615 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_sip.c

@@ -14531,7 +14531,8 @@ static void state_notify_build_xml(struct state_notify_data *data, int full, con
 		else
 			ast_str_append(tmp, 0, "<status><basic>%s</basic></status>\n", (local_state != NOTIFY_CLOSED) ? "open" : "closed");
 
-		if (allow_notify_user_presence(p) && (data->presence_state > 0)) {
+		if (allow_notify_user_presence(p) && (data->presence_state != AST_PRESENCE_INVALID)
+				&& (data->presence_state != AST_PRESENCE_NOT_SET)) {
 			ast_str_append(tmp, 0, "</tuple>\n");
 			ast_str_append(tmp, 0, "<tuple id=\"digium-presence\">\n");
 			ast_str_append(tmp, 0, "<status>\n");