Fix for bug 3415286. The persistent properties are normally read early
in the boot process after /data is mounted. However, for an encrypted
system, at that point /data is a tmpfs ramdisk. This change adds a new
command to init (load_persist_props) to read the persistent properties,
and adds an action to init.rc to load the persistent properties. This
action is triggered by setting a property in vold, but that's in a
different CL.
Change-Id: I74b3057974ee6029c29d956b76fef5566700d471
Ken Sumrall