refer to updateLRUClock's comment REDIS_LRU_CLOCK_MAX is 22 bits,but #define...

refer to updateLRUClock's comment REDIS_LRU_CLOCK_MAX is 22 bits,but #define REDIS_LRU_CLOCK_MAX ((1<<21)-1) only 21 bits

src/redis.h

@@ -382,7 +382,7 @@ typedef long long mstime_t; /* millisecond time type. */
 /* A redis object, that is a type able to hold a string / list / set */
 
 /* The actual Redis Object */
-#define REDIS_LRU_CLOCK_MAX ((1<<21)-1) /* Max value of obj->lru */
+#define REDIS_LRU_CLOCK_MAX ((1<<22)-1) /* Max value of obj->lru */
 #define REDIS_LRU_CLOCK_RESOLUTION 10 /* LRU clock resolution in seconds */
 typedef struct redisObject {
     unsigned type:4;