initialize always TGraph.fFunctions even when using the default TGraph ctor.  This fix problem reported at https://savannah.cern.ch/bugs/?45607
initialize always TGraph.fFunctions even when using the default TGraph ctor. 
This fix problem reported at https://savannah.cern.ch/bugs/?45607


git-svn-id: ecbadac9c76e8cf640a0bca86f6bd796c98521e3@27072 27541ba8-7e3a-0410-8455-c3a389f83636

dawehner/root,dawehner/root,bbannier/ROOT,dawehner/root,bbannier/ROOT,dawehner/root,dawehner/root,bbannier/ROOT,bbannier/ROOT,bbannier/ROOT,dawehner/root,dawehner/root,bbannier/ROOT,bbannier/ROOT,dawehner/root