Bug: 26778031
Test: Boots, reboots, sector 0 of userdata encrypted
Make sure an FDE device, both default and password protected,
boots.
Make sure an FBE device without metadata encryption boots.
Change-Id: Ic44a32ce7e9b978e9c9e2dc112b26206741c838d
Support encrypting metadata in /userdata using the dm-default-key
driver with a key in the /metadata partition.
Bug: 29189559
Test: Angler & Marlin build and boot
Change-Id: I716b117508d4bb4f6a4039293acb848cbc60f67b