Lock agents while removing pending ones

git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@1168 65c4cc65-6c06-0410-ace0-fbb531ad65f3

channels/chan_agent.c

@@ -348,7 +348,9 @@ static int agent_hangup(struct ast_channel *ast)
 	ast_pthread_mutex_unlock(&p->app_lock);
 
 	if (p->pending) {
+		ast_pthread_mutex_lock(&agentlock);
 		agent_unlink(p);
+		ast_pthread_mutex_unlock(&agentlock);
 	}
 	if (p->dead)
 		free(p);