Apexd: Expose mountPackage to binder/cmd

Change mountPackage to return StatusOr and make it available by adding
it to the binder interface.

Test: mmma system/apex/apexd
Test: pushd system/apex/apexd ; atest ; popd
Test: adb push system/apex/apexd/apexd_testdata/test.apex /data/local/tmp && adb shell 'setenforce 0 ; cmd apexservice installPackage /data/local/tmp/test.apex && cmd apexservice mountPackage /data/apex/com.android.example.apex@1.apex'
Change-Id: Ib520f5d6a270e6ff1e66999e2c97d6e1aa1418d4
5 files changed
tree: 9bfc67e7d211a836d0f2f39439333b7740857e11
  1. apexd/
  2. apexer/
  3. testdata/
  4. Android.bp
  5. OWNERS
  6. PREUPLOAD.cfg