Apexd: Add Unmount function and use it in preinstall

Add a function to unmount an inactive package. Use it in the
preinstall code to be clean.

Bug: 119261380
Test: atest apexservice_test
Change-Id: I23c2dc9a751401b0d96bf165d4257f4f1216198c
6 files changed
tree: 19a16a4a84cff609be5acbf78b21781fe119fb5d
  1. apexd/
  2. apexer/
  3. tests/
  4. OWNERS
  5. PREUPLOAD.cfg