target: Fix COMPARE_AND_WRITE caw_sem leak during se_cmd quiesce

This patch addresses a COMPARE_AND_WRITE se_device->caw_sem leak,
that would be triggered during normal se_cmd shutdown or abort
via __transport_wait_for_tasks().

This would occur because target_complete_cmd() would catch this
early and do complete_all(&cmd->t_transport_stop_comp), but since
target_complete_ok_work() or target_complete_failure_work() are
never called to invoke se_cmd->transport_complete_callback(),
the COMPARE_AND_WRITE specific callbacks never release caw_sem.

To address this special case, go ahead and release caw_sem
directly from target_complete_cmd().

(Remove '&& success' from check, to release caw_sem regardless
 of scsi_status - nab)

Signed-off-by: Jiang Yi <jiangyilism@gmail.com>
Cc: <stable@vger.kernel.org> # 3.14+
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>