Coverity fixes


git-svn-id: https://root.cern.ch/svn/root/trunk@48295 27541ba8-7e3a-0410-8455-c3a389f83636
chnge GetBinUpEdge as suggested in  https://savannah.cern.ch/bugs/?99815


git-svn-id: https://root.cern.ch/svn/root/trunk@48296 27541ba8-7e3a-0410-8455-c3a389f83636
fix compiler warning


git-svn-id: https://root.cern.ch/svn/root/trunk@48297 27541ba8-7e3a-0410-8455-c3a389f83636