libconfuse: bump to version 2.8

Since libconfuse now has a proper release tar ball, this also adds a
hash, removes autogen, and removes a patch that is no longer needed.

Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>