vold_prepare_subdirs: prepare /data/misc_[ce|de]/rollback.

These directories are managed by installd and used to store
snapshots of application data directories in order to roll them
back in the case of bad updates.

Bug: 112431924
Test: make, device boot & manual verification.

Change-Id: Ieaca697a45d013937327e0f16f36b9b1eaad6b22
1 file changed