Remove pending message when Close Complete received.

Remove pending message when Close Complete received.

When parse_before_bind() is called and a close message is sent, a
pending message is created but it is not removed later on. For usual
close message read_kind_from_backend() does not remove the pending
message because CloseComplete() does it later on. But in the code path
for parse_before_bind() gets called, CloseComplete() did not remove
the pending message. This brings loosing sync of pending messages and
messages from backend, which could cause a hang in
read_kind_from_backend().