block/dirty-bitmap: remove assertion from restore

When making a backup of a dirty bitmap (for transactions), we want to
restore that backup whether or not the bitmap is enabled.

It is perfectly valid to write into bitmaps that are disabled. It is
only illegitimate for the guest to have done so.

Remove this assertion.

Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Signed-off-by: John Snow <jsnow@redhat.com>
Message-Id: <20181221093529.23855-3-jsnow@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>
1 file changed