B&C News Briefs Æ The Federal Home Loan Bank of Boston has amended its purchase policies to ferret out potentially abusive mortgages. In an update issued last week, the bank said that it won’t accept as pledged collateral any mortgages with rates or fees that exceed the thresholds established by the federal HomeOwnership and Equity Protection Act, loans that have been identified by a federal regulator as “possessing predatory characteristics,” or loans that include single