Adding fix for attachbottom patch

patch/attachx.c

@@ -34,8 +34,9 @@ attachx(Client *c)
 	for (at = c->mon->clients; at && at->next; at = at->next);
 	if (at) {
 		at->next = c;
+		c->next = NULL;
 		return;
 	}
 	#endif
 	attach(c); // master (default)
-}
+}