Use average interactions per crossing from the lumi conditions data.
requested to merge goetz/athena:TRTErrorScaling_master_work_around_for_mu_not_set_in_event_info into master
Use the average interactions per crossing from the luminosity conditions data for the TRT drift circle mu corrections. This works around the problem that the average interactions per crossing is currently not set in the xAOD event info.
The mu correction is current disabled in the configuration to avoid output changes wrt. the current version in master.