Avoid -fsanitize=float-divide-by-zero

...as happens with `--convert-to pdf xls/fdo53482-2.xls` with xls/fdo53482-2.xls
as obtained by xls/fdo53482-2.xls (i.e., the attachment at
<https://bugs.documentfoundation.org/show_bug.cgi?id=53482#c25>):

> chart2/source/tools/PolynomialRegressionCurveCalculator.cxx:190:38: runtime error: division by zero
>  #0 in chart::PolynomialRegressionCurveCalculator::recalculateRegression(com::sun::star::uno::Sequence<double> const&, com::sun::star::uno::Sequence<double> const&) at chart2/source/tools/PolynomialRegressionCurveCalculator.cxx:190:38
>  #1 in chart::VSeriesPlotter::createRegressionCurvesShapes(chart::VDataSeries const&, com::sun::star::uno::Reference<com::sun::star::drawing::XShapes> const&, com::sun::star::uno::Reference<com::sun::star::drawing::XShapes> const&, bool) at chart2/source/view/charttypes/VSeriesPlotter.cxx:1341:22
>  #2 in chart::AreaChart::impl_createSeriesShapes() at chart2/source/view/charttypes/AreaChart.cxx:539:17
>  #3 in chart::AreaChart::createShapes() at chart2/source/view/charttypes/AreaChart.cxx:965:5
>  #4 in chart::ChartView::impl_createDiagramAndContent(chart::CreateShapeParam2D const&, com::sun::star::awt::Size const&) at chart2/source/view/main/ChartView.cxx:1608:25
>  #5 in chart::ChartView::createShapes2D(com::sun::star::awt::Size const&) at chart2/source/view/main/ChartView.cxx:3037:41

The division aSumError/aSumTotal is there ever since the code's introduction in
e6a0cc2d6cb37bf4e04861173c7e55b307513778 "fdo#35712 polynomial and moving
average regression lines", and quikee suggested this fix on IRC.

Change-Id: Ic9cd7b8aaa8451e1230fca8137bad29e28f6477f
Reviewed-on: https://gerrit.libreoffice.org/74036
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

0 files changed, 0 insertions, 0 deletions