[Run2_2017] TTJets genMET-80 addition for Autumn18
Created by: aperloff
Add the Autumn18 TTJets_*_GenMet-80 samples to the Autumn18 MC sample dict and the cross section dict.
Created by: aperloff
Add the Autumn18 TTJets_*_GenMet-80 samples to the Autumn18 MC sample dict and the cross section dict.