A quick fix, recommended by John Patton (tiltjlp), the master and chief advocate of dry tobacco, is to fill a pipe and breathe down into the bowl a couple of times, and let it sit for a few minutes.
Normally most folks prefer their tobacco on the dry side as the flavor gains a subtle clarity; but former cigar and cigarette smokers usually mistake it for being stale. Greg Pease has written on this topic a bit too.
Besides John Patton and some C&D blends, Russ Ouellette's LJ Heart Burley is a bone dry tobacco that, as an after dinner smoke, is to die for -- and it has the consistency and cut of aquarium fish food flakes!
My advice is to ignor the advice of the people telling you to rehydrate it! Unless it has crumbled into powder, it's probably meant to be at the moisture level it was packaged. So there you have it: both sides of the issue. And on this one, my advice is right.