Fix system server crash when told to init backup transports

Refactor + merge gone awry; and pay attention to typed vs typeless
use of toArray().

Change-Id: I031ded949a6e3f2a296c9bf007129e4ebf796a4b
Fix: 67419822
Test: adb root && adb wait-for-device && \
      adb shell cmd activity broadcast -a android.app.backup.intent.INIT