First of all, I would NOT drill out that bracket. I agree that based on the picture, it looks like the culprit is that it was made slightly too long, or maybe mislocated slightly to the left, but assuming that's not going cause you and edge distance problem on down the road with whatever the other side of it attaches to (something worth checking now if you can) The easiest way to deal with this is to just relieve the skin and maybe the underlying rib flange if it's interfering as well? (This assumes that you can relieve the stuff other than the bracket without running into an edge distance problem).
What I would do;
1. Drill out a few of those -3 rivets in the edge of the skin so that you can flex the skin up off the underlying structure a bit.
2. Slide a thin stainless steel putty knife under the skin in the problem area to protect the underlying structure.
3. use a ruler, feeler gauge, #40 drill bit etc. to raise the skin edge up off your spar protecting putty knife.
3. Relieve the interference by sanding a nicely radiuses notch in the skin with emory cloth, sandpaper, jewelers file, whatever. Looks like it only needs a few thousandths, so I don't see the need to bust out the dremmel, rotary file, or any other potentially spar destroying power tool that you happen to have.
5. remove putty knife and other stuff.
4. squeeze new skin rivets.
done.