TableView: make rowCount and columnCount read-only

Change-Id: Ia2f867293b15bdc82b4996818501397b6fa18f23
Reviewed-by: J-P Nurmi <jpnurmi@digia.com>

src/controls/TableView.qml

@@ -202,10 +202,10 @@ ScrollView {
 
     /*! \qmlproperty int TableView::rowCount
     The current number of rows */
-    property alias rowCount: listView.count
+    readonly property alias rowCount: listView.count
 
     /*! The current number of columns */
-    property int columnCount: columns.length
+    readonly property int columnCount: columns.length
 
     /*! \qmlproperty string TableView::section.property
         \qmlproperty enumeration TableView::section.criteria