DEBUG CMDKEYS added for getKeysFromCommand() testing.
DEBUG CMDKEYS added for getKeysFromCommand() testing.

Examples:

    redis 127.0.0.1:6379> debug cmdkeys set foo bar
    1) "foo"
    redis 127.0.0.1:6379> debug cmdkeys mget a b c
    1) "a"
    2) "b"
    3) "c"
    redis 127.0.0.1:6379> debug cmdkeys zunionstore foo 2 a b
    1) "a"
    2) "b"
    3) "foo"
    redis 127.0.0.1:6379> debug cmdkeys ping
    (empty list or set)

Hailei/redis,slfs007/mk-redis,HunanTV/redis,ksarch-saas/redis,ttuna/msot-redis,louisliangjun/redis,jxwr/redis,MSOpenTech/redis,xuzhezhaozhao/redis_reading,slfs007/mk-redis,ttuna/msot-redis,ttuna/msot-redis,darksideofthemoo/redis-histogram,jxwr/redis,slfs007/mk-redis,HunanTV/redis,maodeyi/redis_lua,Hailei/redis,himoca/redis,himoca/redis,xuzhezhaozhao/redis_reading,MSOpenTech/redis,ksarch-saas/redis,maodeyi/redis_lua,darksideofthemoo/redis-histogram,spearhead-ea/redis,maodeyi/redis_lua,splitice/redis,HunanTV/redis,ttuna/msot-redis,MSOpenTech/redis,louisliangjun/redis,ramonsnir/redis,darksideofthemoo/redis-histogram,MSOpenTech/redis,spearhead-ea/redis,louisliangjun/redis,ttuna/msot-redis,HunanTV/redis,xuzhezhaozhao/redis_reading,darksideofthemoo/redis-histogram,himoca/redis,splitice/redis,ramonsnir/redis,louisliangjun/redis,ksarch-saas/redis,MSOpenTech/redis,Hailei/redis,Hailei/redis,ramonsnir/redis,jxwr/redis,splitice/redis,spearhead-ea/redis,ksarch-saas/redis,splitice/redis,xuzhezhaozhao/redis_reading