Fixed a crash-on-exit, when the validation message is up when closing.

Delete the hint window instnce before the grid windows get deleted,
since the hint window is now a child window of one of the grid
window instances.

sc/source/ui/view/tabview5.cxx

@@ -185,6 +185,8 @@ ScTabView::~ScTabView()
 
     delete pSelEngine;
 
+    // Delete this before the grid windows, since its a child window of one of them.
+    mpInputHintWindow.reset();
     for (i=0; i<4; i++)
         delete pGridWin[i];