Get rid of group_info

Get rid of group_info

This is 8 bits which hold how many groups the key has, what to do the
key group is out of bound and the group to redirect to if want to. This
may save a few bytes, but is really annoying. So instead, just lay out
the fields separately. We can optimize later in a sane way, with pahole,
bitfields, etc. if we want.

Signed-off-by: Ran Benita <ran234@gmail.com>