cqerl_client: Fix sleep-state message handling

This change fixes two problems in the handle_info/3 clause for the sleep
state.

* The pattern for valid response frames was out of sync with the return
  values for cqerl_protocol:response_frame/2.  As a result, the slots
  and queries fields in #client_state{} were never updated.

* The logic for managing delayed bytes did not account for the
  possiblity that BinaryMsg can contain the final fragment of one frame
  and the initial fragment of the next.  In this situation, it will
  discard the initial fragment, thereby wedging the framing state machine.