rmt doesn't support distribution modula & random

[patpatbear]

rmt redis_twem_backend_idx and redis_twem_backend_node use ketama distribution
regardless of config. it will cause seriours data corruption if user use modula or random distribution.

redis_twem_backend_idx(redis_group *rgroup, uint8_t *key, uint32_t keylen)
{
    uint32_t idx, hash;
    int distribution = DIST_KETAMA;
    struct continuum *continuum;
    
   ...
}

[iKenApple]

@patpatbear please check this out #22

[patpatbear]

cool! seems fine for me ^_^ @iKenApple