Add /apex tmpfs mount and mount it.

APEX filesystem images will now be mounted in /apex.

Also, make sure /data/apex is created with the right ACL.

Bug: 112455435
Test: flash and wipe, /apex is mounted as tmpfs, /data/apex is created
Change-Id: Ie27775e9f40a27b510272f212762624a04e94f1d
2 files changed