LBJ THANKS CHELF FOR HELP ON IMMIGRATION BILL, ASKS FOR HELP ON REPEAL OF SECTION 14-B OF TAFT-HARTLEY ACT; CHELF EXPLAINS PROBLEMS BILL WILL CAUSE HIM; LBJ'S VOTING RECORD ON ACT; CURRENT LABOR SITUATION; CHELF THANKS LBJ FOR THE WAY HE HAS TREATED HIM