[ntuple] increase default cluster size from 8k to 64k entries
[ntuple] increase default cluster size from 8k to 64k entries

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