Fix API level compatibility

traccar-client/src/main/java/org/traccar/client/TraccarService.java

@@ -116,11 +116,16 @@ public class TraccarService extends Service {
         wakeLock.release();
     }
 
+    @TargetApi(Build.VERSION_CODES.ECLAIR)
     public double getBatteryLevel() {
+        if (android.os.Build.VERSION.SDK_INT > Build.VERSION_CODES.ECLAIR) {
             Intent batteryIntent = registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
             int level = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
             int scale = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, 1);
             return (level * 100.0) / scale;
+        } else {
+            return 0;
+        }
     }
 
     private PositionProvider.PositionListener positionListener = new PositionProvider.PositionListener() {