Padding a passphrase with null chars to arrive at a 32-byte length
later forces a user to also pass null chars via the term when
attempting to manually unlock a subvolume via the fscrypt cli tools.
This also had a side-effect of truncating any longer length passphrase
down to a shorter 32-byte length.
fixup for:
cfea8d756231e7eda5150e33a7f5711cfcf3aafb
dd0e1988c08e75ce9564854eab93bb0826a9532d
Signed-off-by: Michael Fritch <mfritch@suse.com>
3410687855