tdf#152517 Fix gen backend treeview ctrl+minus behavior

For gen type backends, makes the cursor node and all sub nodes
collapsed on ctrl+minus key input.

Change-Id: I53730aca29dd47766cfe8b4cdc81539633ebd8c9
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/144286
Tested-by: Jenkins
Reviewed-by: Jim Raykowski <raykowj@gmail.com>
diff --git a/vcl/source/treelist/svimpbox.cxx b/vcl/source/treelist/svimpbox.cxx
index 63b4d92..b5efa69 100644
--- a/vcl/source/treelist/svimpbox.cxx
+++ b/vcl/source/treelist/svimpbox.cxx
@@ -2392,9 +2392,12 @@ bool SvImpLBox::KeyInput( const KeyEvent& rKEvt)

        case KEY_SUBTRACT:
            if (m_pView->IsExpanded(m_pCursor))
                m_pView->Collapse(m_pCursor);
            if (bMod1)
                CollapseTo(m_pTree->GetRootLevelParent(m_pCursor));
            {
                if (bMod1)
                    CollapseTo(m_pCursor);
                else
                    m_pView->Collapse(m_pCursor);
            }
            break;

        case KEY_MULTIPLY: