Otherwise, exports and block devices are not properly shut down and
closed, unless the users explicitly issues blockdev-del and
block-export-del commands for each of them.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20201027190600.192171-17-mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>