nDelta overwritten on all branches except default

which claims to only exist to avoid a compiler warning. So drop
GetDelta() call and fold the default into the Drag case instead

Change-Id: I978bb38ccff34687bb70453abe416a9c73228655
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/137808
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
diff --git a/sc/source/ui/view/tabview.cxx b/sc/source/ui/view/tabview.cxx
index 898181c..c737317 100644
--- a/sc/source/ui/view/tabview.cxx
+++ b/sc/source/ui/view/tabview.cxx
@@ -1086,7 +1086,7 @@ IMPL_LINK( ScTabView, ScrollHdl, ScrollBar*, pScroll, void )
        }
    }

    tools::Long nDelta = pScroll->GetDelta();
    tools::Long nDelta(0);
    switch ( eType )
    {
        case ScrollType::LineUp:
@@ -1109,6 +1109,7 @@ IMPL_LINK( ScTabView, ScrollHdl, ScrollBar*, pScroll, void )
            if ( pScroll == aVScrollBottom.get() ) nDelta = aViewData.VisibleCellsY( SC_SPLIT_BOTTOM );
            if (nDelta==0) nDelta=1;
            break;
        default: // added to avoid warnings
        case ScrollType::Drag:
            {
                // only scroll in the correct direction, do not jitter around hidden ranges
@@ -1133,10 +1134,6 @@ IMPL_LINK( ScTabView, ScrollHdl, ScrollBar*, pScroll, void )
                nPrevDragPos = nScrollPos;
            }
            break;
        default:
        {
            // added to avoid warnings
        }
    }

    if (nDelta)