veritysetup: add --root-hash-file option
Allow to pass the root hash via a file, rather than verbatim on the command line, for the open/verify/format actions. It is much more convenient when using veritysetup in scripts.
Allow to pass the root hash via a file, rather than verbatim on the command line, for the open/verify/format actions. It is much more convenient when using veritysetup in scripts.