Insufficient AccessController covering permission check

  List<Cell> list = (List<Cell>)entry.getValue();
  if (list == null || list.isEmpty()) {
	get.addFamily(col);
  } else {
	for (Cell cell : list) {
	  get.addColumn(col, CellUtil.cloneQualifier(cell));
	}
  }

When a delete family Mutation comes, a Cell will be added into the list with Qualifier as null. (See Delete#deleteFamily(byte[])). So it will miss getting added against the check list == null || list.isEmpty(). We will fail getting the cells under this cf for covering permission check.