libblkid: Abort after an incorrect checksum

Log incorrect checksums and stop the superblock probing loop when
one is encountered.
This is to avoid exposing backend devices that are supposed
to be used through a stacked device (like raid or bcache).

Signed-off-by: Gabriel de Perthuis <g2p.code@gmail.com>
bcache support by Rolf Fokkens

From https://bugzilla.redhat.com/show_bug.cgi?id=1001120#c11
bcache: use blkid_probe_set_csum

Signed-off-by: Gabriel de Perthuis <g2p.code@gmail.com>
wipefs: Also wipe superblocks with bad checksums

Signed-off-by: Gabriel de Perthuis <g2p.code@gmail.com>