dex2oat fails when upgrading unlabeled asec containers.

Steps to reproduce:

1) Install a forward locked app on Android 4.1
  adb install -l foo.apk
2) Upgrade to tip-of-tree

Addresses the following denial:

  <4>[  379.886665] type=1400 audit(1405549869.210:4): avc: denied { read } for pid=2389 comm="dex2oat" path="/mnt/asec/jackpal.androidterm-1/pkg.apk" dev=dm-0 ino=12 scontext=u:r:dex2oat:s0 tcontext=u:object_r:unlabeled:s0 tclass=file

(cherry picked from commit 270be6e8)

Change-Id: I58dc6ebe61a5b5840434077a55f1afbeed602137

dex2oat can't access file descriptors associated with asec_apk_files.
This breaks installing forward locked apps, and generates the following
denial:

  type=1400 audit(0.0:18): avc: denied { read } for path="/mnt/asec/com.example.android.simplejni-1/pkg.apk" dev="dm-0" ino=12 scontext=u:r:dex2oat:s0 tcontext=u:object_r:asec_apk_file:s0 tclass=file

Steps to reproduce:

  $ adb install -r -l SimpleJNI.apk

Expected:

  app installs

Actual:

  app fails to install.

Bug: 16328233

(cherry picked from commit 5259c5e6)

Change-Id: I1969b9ae8d2187f4860587f7ff42d16139657b5b

Change-Id: Ic9dde806a30d3e7b9c4a066f247a9207fe9b94b4