Support bmgr wipe also for full backup apps

Previously we'd only really clear data for K/V packages,
now we consult with the journal of ever backed apps.

Bug: 28405555
Test: manual (adb shell bmgr wipe com.google.android.gms/.backup.BackupTransportService com.android.wallpaperbackup
      after adb shell bmgr backupnow --all)
Test: m -j RunFrameworksServicesRoboTests
Test: runtest -p com.android.server.backup frameworks-services
Change-Id: If99cb2c8ab9ddc05386d634818f4585ec47efc00