Adding vendor_apex_file for /vendor/apex

apexd needs to read /vendor/apex dir and files in it.

Bug: 131190070
Bug: 123378252
Test: 1. Add apex to /vendor/apex
      -> see if boot succeeds with new policy
      2. Add flattened apex to /vendor/apex
      -> see if only root files are labelled as vendor_apex_file

Change-Id: I37795ab6d659ac82639ba5e34d628fe1b5cdb350
8 files changed