ovs-ofctl: Free group buckets.

To some extent this is cosmetic because ovs-ovfctl will immediately
exit. However, it does seem to be in keeping with freeing 'gms' in
ofctl_group_mod_file().

Found by inspection using make check-valgrind.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
ofp-print-ofctl: Free group buckets.

Found by inspection using make check-valgrind.

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>