We want to remove the deprecated 'CryptsetupEncryptor' encryptor, but
'LuksEncryptor' and the 'Luks2Encryptor' subclass depend on it. Fix this
by copying across the common code, allowing us to remove
'CryptsetupEncryptor' in a future change.
Change-Id: I7c523dc982803b337a51c111b01e170bba7c341f
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>
e6ad5ac7d6