Memcontrol: remove a stray ` sign from comment.

index 631002d..887155b 100644
@@ -884,7 +884,7 @@ int mem_cgroup_force_empty(struct mem_cgroup *mem)
 	css_get(&mem->css);
 	/*
 	 * page reclaim code (kswapd etc..) will move pages between
-`	 * active_list <-> inactive_list while we don't take a lock.
+	 * active_list <-> inactive_list while we don't take a lock.
 	 * So, we have to do loop here until all lists are empty.
 	 */
 	while (mem->res.usage > 0) {