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