Meta server: rework / fix chunk server authentication by ensuring that no pending / unread data left in the read buffer, keeping authentication rpc around until the replay goes into the "wire" (os socket really) completely, in order to correctly switch in, if required, ssl filter. Declare error in the case if authentication rpc receive after chunk server hello. Disconnect chunk server in case of authentication rpc error immediately after authentication rcp reply goes onto the "wire". Fix client state machine authentication rcp error handling: do not override error status in case if read buffer isn't empty.