Change the order of data member initializers

To suppress compiler warning that the order of member initializers
does not match the order in which they are executed.

src/propgrid/advprops.cpp

@@ -113,8 +113,8 @@ class wxPGSpinButton : public wxSpinButton
 {
 public:
     wxPGSpinButton() : wxSpinButton()
-        , m_hasCapture(false)
         , m_spins(1)
+        , m_hasCapture(false)
     {
         Bind(wxEVT_LEFT_DOWN, &wxPGSpinButton::OnMouseLeftDown, this);
         Bind(wxEVT_LEFT_UP, &wxPGSpinButton::OnMouseLeftUp, this);