[ntuple] fix compiler warnings
[ntuple] fix compiler warnings

karies/root,karies/root,olifre/root,karies/root,karies/root,olifre/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,karies/root,karies/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,olifre/root,karies/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,olifre/root,olifre/root