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
diff --git a/rootdir/init.rc b/rootdir/init.rc
index f39ea7c..826accd 100644
--- a/rootdir/init.rc
+++ b/rootdir/init.rc
@@ -269,6 +269,12 @@
     # that they can be chown'd to system:system later on boot
     write /sys/class/leds/vibrator/trigger "transient"
 
+    # Setup APEX mount point and its security context
+    mount tmpfs tmpfs /apex nodev noexec nosuid
+    chmod 0755 /apex
+    chown root root /apex
+    restorecon /apex
+
 # Healthd can trigger a full boot from charger mode by signaling this
 # property when the power button is held.
 on property:sys.boot_from_charger_mode=1
@@ -523,6 +529,8 @@
 
     mkdir /data/anr 0775 system system
 
+    mkdir /data/apex 0770 root root
+
     # NFC: create data/nfc for nv storage
     mkdir /data/nfc 0770 nfc nfc
     mkdir /data/nfc/param 0770 nfc nfc