Launch processes running under the 'bluetooth' uid with CAP_WAKE_ALARM.

This is required since bluedroid needs to set wake alarms and timers.
Going through JNI back into Java code and then across Binder to
AlarmManager is both inefficient and doesn't provide the resolution
required for functions like A2DP.

Change-Id: I619be0b18a9e7ac2567b7c68ba84fcd15eecf715