nvme/pci: Don't mark IOD as aborted if abort wasn't sent

This patch sets the aborted flag only if an abort was sent, reducing
excessive kernel message spamming for completed IO that wasn't actually
aborted.

Reported-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>