An overloaded drawPolyPolygon for zero transparency case used to
exist and it used applyColor to fill cairo path. It was removed
by commit 7034311d and the new
transparency-aware drawPolyPolygon missed cairo_set_operator call
that is present in applyColor. This works OK most of the time
but breaks sometimes when no transparency (~no antialiasing)
is involved.

To fix that add transparency argument to applyColor and use it
where applicable

Change-Id: Ib1b077e38e7f5d30778434d45be67284407a7d16
Reviewed-on: https://gerrit.libreoffice.org/71759
Tested-by: Jenkins
Reviewed-by: Christian Lohmaier <lohmaier+LibreOffice@googlemail.com>