Modify THcAerogel.cxx

Modify THcAerogel::CoarseProcess



For each PMT, fGoodPosAdcMult.at(npmt) was being set to the total number of positive PMTs with an
adc hit and fGoodNegAdcMult.at(npmt) was being set to the total number of negative PMTs with an
adc hit.

To be like the other dectectors make fGoodPosAdcMult.at(npmt)
and  GoodNegAdcMult.at(npmt) be the number of adc hits for that particular
PMT.