Minor modification to tree_hash

eth2/utils/ssz/src/tree_hash.rs

@@ -30,6 +30,7 @@ pub fn merkle_hash(list: &mut Vec<Vec<u8>>) -> Vec<u8> {
                 // Hash two chuncks together
                 new_chunkz.append(&mut hash(two_chunks));
             }
+            chunk_size = HASHSIZE;
         }
         chunkz = new_chunkz;
     }