GEAR_* rename

- change to GEAR_PARK and GEAR_LOW
- also remove some build warnings

bug: 27549456
Change-Id: I9062c4570afe5cacd6a17f1cb196273a719b0a97
diff --git a/tests/vehicle/vehicle_test_fixtures.h b/tests/vehicle/vehicle_test_fixtures.h
index 15cafaa..a9572ba 100644
--- a/tests/vehicle/vehicle_test_fixtures.h
+++ b/tests/vehicle/vehicle_test_fixtures.h
@@ -55,7 +55,7 @@
     return 0;
 }
 
-int VehicleErrorCallback(int32_t error_code, int32_t property, int32_t operation) {
+ int VehicleErrorCallback(int32_t /*error_code*/, int32_t /*property*/, int32_t /*operation*/) {
     // Do nothing.
     return 0;
 }