Fix for rolling X vs. LB plots
In the current version, data from old version of the histograms (before the axis ranges are shifted) were not being copied over to the new histogram (after the ranges shift), so this is corrected.
In doing so, I found that HistogramFactory was improperly calling the THistSvc::exists
, which only works for TH1 decedents. This now properly accommodates other classes.
See ATLASDQ-685 for details.