StETofHitMaker: Fix unused variable warnings

[plexoos]

g++ -m64 -fPIC -pipe -Wall -Woverloaded-virtual -std=c++0x -Wno-long-long -pthread -Wno-deprecated-declarations -O2 -g -falign-loops -falign-jumps -falign-functions -Dsl79_gcc485 -D__ROOT__ -DNEW_DAQ_READER -I. -IStRoot -I.sl79_gcc485/include -I/opt/software/linux-scientific7-x86_64/gcc-4.8.5/root-5.34.38-l3v6vso6qgojm4l2ctwjojs6trbt4hpn/include -c .sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx -o .sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.o
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx: In member function 'void StETofHitMaker::processStEvent()':
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx:415:27: warning: unused variable 'etofHits' [-Wunused-variable]
         StSPtrVecETofHit& etofHits = etofCollection->etofHits();
                           ^
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx: In member function 'void StETofHitMaker::processMuDst()':
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx:485:16: warning: unused variable 'nHits' [-Wunused-variable]
         size_t nHits = mMuDst->numberOfETofHit();
                ^
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx: In member function 'void StETofHitMaker::fillUnclusteredHitQA(const double&, bool)':
.sl79_gcc485/OBJ/StRoot/StETofHitMaker/StETofHitMaker.cxx:1203:9: warning: unused variable 'eventTime' [-Wunused-variable]
     int eventTime = ( this->GetTime() / 10000 ) * 3600 + ( ( this->GetTime() % 10000 ) / 100 ) * 60 + ( this->GetTime() % 100 );
         ^

[klendathu2k]

LGTM.