Remove keystore entries when package removed

Add a hook into PackageManagerService so that when app IDs are
completely removed, we erase all entries from keystore for those UIDs
that have gone away.

(cherry picked from commit 95e3ee3971915b323e5c13dcfe3b12a4180850cd)

Bug: 3020069
Change-Id: I374258ccc103f8cb3e238f2bf0d1afda0659db94
3 files changed