[Minor] Remove special handling

lualib/lua_bayes_redis.lua

 local function gen_cache_learn_functor(redis_params, learn_script_id, conf)
   local packed_conf = ucl.to_format(conf, 'msgpack')
   return function(task, cache_id, is_spam)
-    local is_per_user = task:get_mempool():has_variable('stat_user')
     local function learn_redis_cb(err, data)
       lua_util.debugm(N, task, 'learn_cache redis cb: %s, %s', err, data)
     end
     lua_redis.exec_redis_script(learn_script_id,
         { task = task, is_write = true, key = cache_id },
         learn_redis_cb,
-        { cache_id, is_spam and "1" or "0", packed_conf, is_per_user and "1" or "0" })
+        { cache_id, is_spam and "1" or "0", packed_conf })
 
   end
 end
     cache_prefix = "learned_ids",
     cache_max_elt = 10000, -- Maximum number of elements in the cache key
     cache_max_keys = 5, -- Maximum number of keys in the cache
-    cache_per_user_mult = 0.1, -- Multiplier for per user cache size
     cache_elt_len = 32, -- Length of the element in the cache (will trim id to that value)
   }
 

lualib/redis_scripts/bayes_cache_learn.lua

 -- key1 - cache id
 -- key3 - is spam (1 or 0)
 -- key3 - configuration table in message pack
 
 local cache_id = KEYS[1]
 local is_spam = KEYS[2]
 local conf = cmsgpack.unpack(KEYS[3])
-local is_per_user = KEYS[4] == "1"
 cache_id = string.sub(cache_id, 1, conf.cache_elt_len)
 
 -- Try each prefix that is in Redis (as some other instance might have set it)
 end
 
 local added = false
-local lim = is_per_user and conf.cache_max_elt * conf.cache_per_user_mult or conf.cache_max_elt
+local lim = conf.cache_max_elt
 for i = 0, conf.cache_max_keys do
   if not added then
     local prefix = conf.cache_prefix .. string.rep("X", i)