Allow callers to prepare CE/DE user storage.

Allow callers to prepare CE/DE user storage.

Give callers the option of preparing CE and/or DE storage.  The
framework will only prepare CE storage after the CE keys have been
unlocked for that user.

When init is calling enablecrypto, kick off the work in a thread so
that we can make other calls back into vold without causing
deadlock.  Leaves blocking call intact for framework callers.

Clean up 'vdc' tool to send useful transaction numbers, and
actually watch for the matching result to come back.  This fixes
race conditions when there are multiple 'vdc' callers.

Also add other system and misc directories to match spec.

Bug: 25796509
Change-Id: Ie4f853db6e387916b845d2b5fb92925d743b063d