Casefolded Encryption support

This adds support for casefolded and encrypted directories.
Fsck cannot check the hashes of such directories because it would
require access to the encryption key to generate the siphash

Bug: 138322712
Test: Set casefolding on an encrypted fs.
      Run fsck on fs with encrypted and casefolded directories
Signed-off-by: Daniel Rosenberg <drosen@google.com>
Change-Id: Icbe9d5bf05e6a80fb1affb4ae9176f01c77095a2
3 files changed