qapi: add qom-path to BLOCK_IO_ERROR event

qapi: add qom-path to BLOCK_IO_ERROR event

We need something more reliable than "device" (which absent in modern
interfaces) and "node-name" (which may absent, and actually don't
specify the device, which is a source of error) to make a per-device
throttling for the event in the following commit.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Message-ID: <20241002151806.592469-2-vsementsov@yandex-team.ru>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>