[RF] Replace TString with std::string in RooSimPdfBuilder
[RF] Replace TString with std::string in RooSimPdfBuilder

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root