DeskClock: Schedule alarms after restore

Fix a bug causing the backup agent's handling of the restore process
to crash, preventing enabled alarms from being scheduled.

Maybe squash with: I1321da4b2250d083c8785386af5ba096cd0e05eb
"DeskClock: Enable backup"

Test: Manual: Steps below:
0. Establish Seedvault backup (easiest to just do a local internal storage backup).
1. Set a few alarms, maybe for 5, 10, and 15 minutes in the future.
2. Run "Backup now" in Seedvault.
3. Once it has finished, turn off the alarms.
4. Run `adb shell bmgr list sets` to get the restore set ID ("${RESTORE_SET_ID}" below).
5. Run `adb shell bmgr restore ${RESTORE_SET_ID} com.android.deskclock`.
6. Within a minute, the alarm icon should appear in the status bar because the alarms have been successfully scheduled. They will sound at the expected time(s).

Change-Id: Ib8bd0cf03f943469fec105b141c58f5f543ccaa0