Qt 5.0 QTreeView. Prevent manual moving of the first section

Qt 5.0 QTreeView. Prevent manual moving of the first section

This prevents the user of moving the leftmost column.

There will be no API to allow move of the tree-structure.
It is very weird to do that, so it shouldn't be a problem.

In case it is a big problem somewhere it can be hacked with:
QTableView unused;
unused.setVerticalHeader(tree->header());
tree->header()->setParent(tree);
unused.setVerticalHeader(new QHeaderView(Qt::Horizontal));

Task-number: QTBUG-332

Change-Id: I3a251c8d0fd472ec0ad7edb20a7f3e00af7e0da8
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>