AppOps: Don't apply OP_ALARM_WAKEUP to system components

System can freely invoke and manage alarms. Preventing it from doing
so interferes with remote components like the backupmanager (backing up alarms)
due to the mismatched uids between the invoking app and the running
service that takes the action.

Change-Id: I079df8d2522642d6d9194781207df7dd67b715b2