Enable upgrading persistent APKs on boot.

Bug: 131046856
Test: marked the NetworkStack APK as persistent, verified that
without this patch:
  - adb install networkstack.apk fails
  - adb install --staged networkstack.apk fails (after reboot)
with this patch:
  - adb install networkstack.apk fails
  - adb install --staged networkstack.apk succeds (after reboot)
Change-Id: I346d772e1f4aed94f6faead3b6455efc4666b651