After updating to Minecraft 1.8, I started a new single player world, started gathering resources.

When I finally had enough iron to make a sword and full armor, I started to kill Creepers, who until then were way out of my league. (Died more than once by them.)

After killing a dozen Creepers, none of them had dropped any gunpowder. That's when I dove into the bugtracker to see if this as already reported and was shocked to find no-one seemed to have done so... So here I am, reporting this.