This change adds a "verify" fs_mgr flag specifying that
the device in question should be verified.
Devices marked with this flag are expected to have a
footer immediately after their data containing all
the information needed to set up a verity instance.
Change-Id: I10101f2c3240228ee0932e3767fe35e673d2e720
Instead of specifying in init what to mount, and having various hacks in init
itself to deal with encryption, use a filesystem manager library to do the
work, that can also be invoked by vold when mounting an encrypted volume.
Keep all the magic filesystem info an a device specific fstab file.
Change-Id: Ib988f1e4fb0638ba1d5fd98407fa6d8cf862aaca
