Set total_count of handler for correct work of session's checkers

Also quorum_lookup doesn't set a reply_error, the reason is:
- it's possible to get good responses from the quorum of groups and
  errors from the others and it's not an error in general for quorum_lookup
- it's possible to get only a good result from a group and errors from
  others and it's also not an error for quorum_lookup
If user want to distinguish these cases, he can set a corresponding
checker for session
Fixed test_quorum_lookup and added several tests:

test_partial_quorum_lookup
test_fail_partial_quorum_lookup
test_fail_parallel_lookup
test_fail_quorum_lookup