Remove useless wxAuiMDIClientWindow::SetSelection()

It just called the base class version, so it's better to not have it at
all.

include/wx/aui/tabmdi.h

@@ -201,7 +201,6 @@ public:
     virtual bool CreateClient(wxAuiMDIParentFrame *parent,
                               long style = wxVSCROLL | wxHSCROLL);
 
-    virtual int SetSelection(size_t page) wxOVERRIDE;
     virtual wxAuiMDIChildFrame* GetActiveChild();
     virtual void SetActiveChild(wxAuiMDIChildFrame* pChildFrame)
     {

src/aui/tabmdi.cpp

@@ -763,11 +763,6 @@ bool wxAuiMDIClientWindow::CreateClient(wxAuiMDIParentFrame* parent, long style)
     return true;
 }
 
-int wxAuiMDIClientWindow::SetSelection(size_t nPage)
-{
-    return wxAuiNotebook::SetSelection(nPage);
-}
-
 wxAuiMDIChildFrame* wxAuiMDIClientWindow::GetActiveChild()
 {
     const int sel = GetSelection();