don't double switch_xml_free

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@4771 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/dialplans/mod_dialplan_xml/mod_dialplan_xml.c

@@ -368,6 +368,7 @@ static switch_caller_extension_t *dialplan_hunt(switch_core_session_t *session,
 
 
 	switch_xml_free(xml);
+	xml = NULL;
 
 	if (extension) {
 		switch_channel_set_state(channel, CS_EXECUTE);