The ifg_list and ifg_member structures are allocated on M_TEMP in
if_addgroup. The ifg_list pointer is properly released in if_delgroup,
but not in if_delgroups.
Fix if_delgroups to release the ifgl pointer as well as the ifgm
pointer, so that we do not leak memory when detaching an interface.
An alternative fix might be to factor out logic for actually freeing the
group memory into a separate function.
Signed-off-by: Jacob Keller <firstname.lastname@example.org>