Battle lines are being drawn within the mortgage financing industry over legislation that would give Ginnie Mae a sphere of influence in the secondary mortgage market that traditionally has been ruled jointly by Fannie Mae and Freddie Mac. Bills introduced late last week by Rep. Marge Roukema, R-NJ, chairwoman of the House Financial Services Subcommittee on Housing and Economic Opportunity, and Sen. Wayne Allard, R-CO, are expected to pit private mortgage insurers and some large