Fixed closing sub-path of wxGraphicsPath with GDI+ renderer.

Close sub-path only if it is really open.

src/msw/graphics.cpp

@@ -1226,6 +1226,8 @@ void wxGDIPlusPathData::AddLineToPoint( wxDouble x , wxDouble y )
 }
 
 void wxGDIPlusPathData::CloseSubpath()
+{
+    if( m_figureOpened )
     {
         m_path->CloseFigure();
         m_figureOpened = false;
@@ -1235,6 +1237,7 @@ void wxGDIPlusPathData::CloseSubpath()
         m_logCurrentPoint = m_figureStart;
         m_logCurrentPointSet = true;
     }
+}
 
 void wxGDIPlusPathData::AddCurveToPoint( wxDouble cx1, wxDouble cy1, wxDouble cx2, wxDouble cy2, wxDouble x, wxDouble y )
 {