ensure m_table is not NULL before trying to access the view

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@43181 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/generic/grid.cpp

@@ -4202,7 +4202,7 @@ wxGrid::~wxGrid()
     // with dangling view pointer
     if ( m_ownTable )
         delete m_table;
-    else if ( m_table->GetView() == this )
+    else if ( m_table && m_table->GetView() == this )
         m_table->SetView(NULL);
 
     delete m_typeRegistry;