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/propgridpagestate.cpp

@@ -191,13 +191,13 @@ wxPropertyGridPageState::wxPropertyGridPageState()
     : m_pPropGrid(NULL)
     , m_properties(&m_regularArray)
     , m_abcArray(NULL)
+    , m_fSplitterX(wxPG_DEFAULT_SPLITTERX)
     , m_currentCategory(NULL)
     , m_width(0)
     , m_virtualHeight(0)
     , m_itemsAdded(false)
     , m_anyModified(false)
     , m_vhCalcPending(false)
-    , m_fSplitterX(wxPG_DEFAULT_SPLITTERX)
     , m_isSplitterPreSet(false)
     , m_dontCenterSplitter(false)
 {