OTTAWA (Reuters) - Some children in Canada are so well-off and so keen on current affairs that they donate thousands of dollars to politicians -- at least, that's what one contender for the leadership of the opposition Liberal Party seems to believe. Former Immigration Minister Joe Volpe hit the spotlight this week after it emerged that a pair of 11-year-old twins and their 14-year-old brother had each donated C$5,400 ($4,900) to his leadership campaign. The parents of the children -- who also donated C$5,400 to Volpe's campaign -- are related to the chairman of generic drug maker Apotex Inc. In...