If a block job reaches failed/cancelled state, or is completed
without pivot then we must remove security driver metadata
associated to the backing chain so that we don't leave any
metadata behind.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1741456Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
ACKed-by: NPeter Krempa <pkrempa@redhat.com>