[+] Generator/HeavyIon
update seq
remove basicHepMCHeavyIonValidation from basicGenTest_seq
Update according to @deguio suggestion. Also protect against null
pointer.
Merge pull request #5193 from BetterWang/HeavyIonDQM_from-CMSSW_7_2_0_pre3

Heavy ion dqm from cmssw 7 2 0 pre3