Session: Error while trying to free lock for ci_session

@spojoneze,

maybe someone will eventually provide solution or creators will make this work in next version(s).
This is ridiculous, response time with memcached is 5s - 6s, when move to files (php.ini session handler memcached) response is 100ms..
But with files it just logout users from time to time, sometimes in 10 minutes sometimes after 3 clicks on site...
In CI 2 it worked like a charm with same server configuration.. It is really annoying