Clint Eastwood's "Changeling" made me feel sympathy, and then anger, and then back around again. It is the factual account of a mother whose little boy disappeared, and of a corrupt Los Angeles Police Department running wild. Angelina Jolie stars as Christine Collins, whose 9-year-old son, Walter, went missing in March 1928. Some months later, the LAPD announced her son had been found alive in DeKalb, Ill.