PHH Mortgage has been struggling with a changing marketplace since Cendant spun it off earlier this year. But its recently announced merger with CUNA Mutual Mortgage Corp. is a good step forward as a stand alone public company for the nation’s largest private label originator. The companies have not released any financial details about the deal, but PHH expects to merge with the Madison, WI, lender by year’s end. PHH will get the company’s…