fix warnings reported by the latest Apple LLVM 4.2 clang++ (based
on llvm 3.2svn). Mostly were:
warning: private field 'fOneDim' is not used [-Wunused-private-field]


git-svn-id: https://root.cern.ch/svn/root/trunk@48467 27541ba8-7e3a-0410-8455-c3a389f83636