The declaration in BarChart.cxx is particularly suspicious, because it
was using a < for the KeyEqual template parameter.
Been there since:
    commit b2c3233e
    Date:   Thu Dec 21 20:08:33 2017 +0900
    chart2: suspend/resume setting rects dirty for 3D shapes

comphelper::OInterfaceCompare is no longer necessary

Change-Id: I8278c4a3d9113a18570ca237cd05d553ec8f3975
Reviewed-on: https://gerrit.libreoffice.org/71537
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>