location: Location Manager wakelock cleanup

Location Providers are now responsible for their own wakelocks and scheduling.

Also fixed a deadlock in LocationManagerService in the code for releasing
wakelocks after client notifications have been received.
The fix is to use the Receiver object and mWakeLock for synchronization
 instead of the global mLock lock.

Signed-off-by: Mike Lockwood <lockwood@android.com>