apparmor: Fix memleak issue in unpack_profile()

Before aa_alloc_profile(), it has allocated string for @*ns_name if @tmpns
is not NULL, so directly return -ENOMEM if aa_alloc_profile() failed will
cause a memleak issue, and even if aa_alloc_profile() succeed, in the
@fail_profile tag of aa_unpack(), it need to free @ns_name as well, this
patch fixes them.

Fixes: 736ec752 ("AppArmor: policy routines for loading and unpacking policy")
Fixes: 04dc715e

 ("apparmor: audit policy ns specified in policy load")
Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: John Johansen <john.johansen@canonical.com>