Tell which packfile is corrupt when we die.
Tell which packfile is corrupt when we die.

The core part detected and died upon seeing a corrupted packfile, but
did not help the user by telling which packfile is corrupt and how.

Signed-off-by: Junio C Hamano <dc50d1021234060e53ec42a77d526afa2fe07479@cox.net>

destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git,destenson/git