ATLANTA — Pro-gun Georgia lawmakers Thursday took revenge on Delta for cutting ties to the National Rifle Association, killing a proposed tax break on jet fuel that would have saved the airline millions. A sweeping tax-cut bill that the Republicans had amended to strip out the fuel-tax exemption passed the GOP-controlled House and Senate by wide margins, just days after Delta reacted to the school massacre in Florida by saying it would no longer offer discount fares to NRA members.