cgconfig: correct freeing default_cgroup
cgconfig: correct freeing default_cgroup

We are freeing up default_cgroup even it has not be allocated,
there is no need to do that.

Yes, it is just a cleanup suggested
by Dhaval Giani <dhaval.giani@gmail.com>

Signed-off-by: Libo Chen <3ddb76ce901f50183fdff8d1ff6862f91b38880c@huawei.com>
Acked-by: Ivana Hutarova Varekova <2e3918a0a366ea7e658a2062ab582c898a7e1b1b@redhat.com>

rafalmiel/libcg,rafalmiel/libcg,rafalmiel/libcg,rafalmiel/libcg