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