[Sitemap] Don't truncate URLs containing ( or )

I'm not sure why it was doing this and @rjc123 is on holiday for a few weeks. It was generating truncated URLs on www.cac.gov.uk, eg:
http://www.cac.gov.uk/media/word/1/i/I___C_Application_Form_
rather than:
http://www.cac.gov.uk/media/word/1/i/I___C_Application_Form_(Reg_10(1)).doc