antirez/redis — pull request #1576 by Hailei (2014-03-04 04:37:45+00:00)
Title: Fix REDIS_LRU_CLOCK_MAX's value

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