Support pre-KitKat properties for update-binary

Google changed the in-memory format for storing properties in 4.4.
Zips containing an older update-binary expect the old format, otherwise
assertions on properties in the update script fail.

This is just enough of the old property service to copy the properties
to the legacy format before running the updater.

Change-Id: I404680384bdc5e952609e295029ab0a0faf743a5
Fix ext4 wiping when no SELinux contexts are defined

Change-Id: I900f42892d47f54b573cc1dbfb551ed2a8f9e8b9
Merge branch 'du44' of https://github.com/DirtyUnicorns-KitKat/bootable_recovery into HEAD