SsrfFilterSortProxyModel was a thin wrapper around QFilterSortProxyModel,
which was intended as a convenience class to avoid deriving from the
latter. The filter and sort functions were replaced by simple function
pointers.
Unfortunately, by using function-pointers, the whole thing was rather
weak as these functions do not have state. The last user was removed
in ac8dcd7f65b78958587ba025280ed4c529b0b519. Therefore, remove the
whole class.
Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>
6137e0bc60