In DiveListView, the result of model() was dynamically cast to
QSortFilterProxyModel. But then, only the virtual match() function
was used. The whole point of virtual functions is that you can
cast them on the base-class and it will execute the function of
the derived class. Thus, remove these casts and operate directly
on the QAbstractItemModel base class.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
