[Rivet] Sigma-unit error bands

[Hendrik Hoeth]

Thus spake David Grellscheid (david.grellscheid at durham.ac.uk):

> I just noticed that the error band plot can show units of sigma.
> However, this means that the label 'MC/Data' is now wrong, or am I
> getting something confused?

That's because compare-histos sets "RatioPlotYLabel", overriding
make-plots' default.

-- 
It pays to be obvious, especially if you have
a reputation for subtlety.    -- Isaac Asimov