I don't think it's a big fire hazard, but the rattle can be major annoying. There are a couple of things you can try to fix it. The cat mounts to the head pipe with a flange that has three bolts and a doughnut gasket. Get new bolts and nuts, and a new gasket, take this joint apart and reassemble it at a different angle (a nasty job, usually involving cutting rusty bolts and fighting to get it apart) If the flanges are badly corroded, to the point of being weakened, this might not be a good idea. The other thing to do, is, as you suggested, bend the pipe. If you try this, it is best to do it with the part off of the car. If you try too hard with it installed, there is a risk of breaking the cat off, as it is usually the weakest point in the system.