Meta server: implement caching of authenticated and effective user and group ids in client protocol state machine. Sset and pass these ids with every kfs ops. Set effective user and group ids for server connections, which presently are only used by recovery, to "no user" and "no group", as the relevant server rpcs used by chunk server ("get alloc" and "lease acquire") have special handling base which uses "from chunk server" flag, instead of effective user and group ids. Update cached user and group ids when / if user and group information changes. Reset client connection if user becomes non valid as the result of the user and group information change.