the first cut of the internal messaging system.

The motivation for this system is to replace the UDP message for
oplocks, but this commit only does the "set debug level" message.

source/smbd/process.c

@@ -131,6 +131,9 @@ static void async_processing(fd_set *fds, char *buffer, int buffer_len)
 		reload_services(False);
 		reload_after_sighup = False;
 	}
+
+	/* check for any pending internal messages */
+	message_dispatch();
 }
 
 /****************************************************************************