Made pistol grip controller work with the drivetrain.

Change-Id: Id5ede34e9a9981c338aaa6118eb5085578a8ecd3
diff --git a/y2018/joystick_reader.cc b/y2018/joystick_reader.cc
index 9286163..2179606 100644
--- a/y2018/joystick_reader.cc
+++ b/y2018/joystick_reader.cc
@@ -50,7 +50,7 @@
  public:
   Reader() {
     drivetrain_input_reader_ = DrivetrainInputReader::Make(
-        DrivetrainInputReader::InputType::kSteeringWheel,
+        DrivetrainInputReader::InputType::kPistol,
         ::y2018::control_loops::drivetrain::GetDrivetrainConfig());
   }