infinite SetDefaultSize->SetPosSize->SetDefaultSize

https://retrace.fedoraproject.org/faf/reports/1278627/

presumably the 'optimal' starting size hits the invalid size path
causing another attempt usin the optimal size, so force a valid
initial fallback size

Change-Id: I6c38ee5e1b90ce41a4550c8a8370e791f5c351b0
diff --git a/vcl/source/window/dialog.cxx b/vcl/source/window/dialog.cxx
index e66155d..95d0e13 100644
--- a/vcl/source/window/dialog.cxx
+++ b/vcl/source/window/dialog.cxx
@@ -664,7 +664,8 @@ Size bestmaxFrameSizeForScreenSize(const Size &rScreenSize)
    else
        h -= 100;

    return Size(w, h);
    return Size(std::max<long>(w, 640 - 15),
                std::max<long>(h, 480 - 50));
}

void Dialog::StateChanged( StateChangedType nType )