Switch to 6 joystick axis now that we are using wpilib 2017

Change-Id: I7ad94990952c932ecf00fd3d82b59d72ba31ebcf
diff --git a/frc971/wpilib/joystick_sender.cc b/frc971/wpilib/joystick_sender.cc
index b4866e9..a490e67 100644
--- a/frc971/wpilib/joystick_sender.cc
+++ b/frc971/wpilib/joystick_sender.cc
@@ -47,7 +47,7 @@
 
     for (int i = 0; i < 4; ++i) {
       new_state->joysticks[i].buttons = ds->GetStickButtons(i);
-      for (int j = 0; j < 4; ++j) {
+      for (int j = 0; j < 6; ++j) {
         new_state->joysticks[i].axis[j] = ds->GetStickAxis(i, j);
       }
       new_state->joysticks[i].pov = ds->GetStickPOV(i, 0);