BARNSTABLE, Mass. — A Brewster man with a history of mental illness and substance abuse problems has been sentenced to 2 ½ years in prison for burning down a Cape Cod church.Adam Finnegan was also sentenced Tuesday in Barnstable Superior Court to 10 years of probation.The sentence was less than the five years requested by prosecutors, in part because the pastor and parishioners at Cape Cod Bible Alliance Church asked the judge for leniency so the 30-year-old Finnegan could get the help he needed.