Remove ProximityAlerts Receiver when last ProximityAlert expires.

Remove the ProximityAlerts update Receiver when the last ProximityAlert expires.
Fixes issue 6900.

Change-Id: Ida1970c084e71df47b204c64986a065cb75d0c13

Author: seanmfoy

services/java/com/android/server/LocationManagerService.java

@@ -1202,8 +1202,9 @@ public void onLocationChanged(Location loc) {
             // Remove expired alerts
             if (intentsToRemove != null) {
                 for (PendingIntent i : intentsToRemove) {
-                    ProximityAlert alert = mProximityAlerts.remove(i);
+                    ProximityAlert alert = mProximityAlerts.get(i);
                     mProximitiesEntered.remove(alert);
+                    removeProximityAlertLocked(i);
                 }
             }
         }