MEDIUM: pools: make pool_put_to_cache() always call pool_put_to_local_cache()

MEDIUM: pools: make pool_put_to_cache() always call pool_put_to_local_cache()

Till now it used to call it only if there were not too many objects into
the local cache otherwise would send the latest one directly into the
shared cache. Now it always sends to the local cache and it's up to the
local cache to free its oldest objects. From a cache freshness perspective
it's better this way since we always evict cold objects instead of hot
ones. From an API perspective it's better because it will help make the
shared cache invisible to the public API.