unpriv tests: also move caller into unbound cgroups

Otherwise the name=systemd cgroup isn't changed to one which
the lxc-unpriv user can write to, causing the test to fail.

This allows lxc-test-unpriv and lxc-test-usernic to pass when run in an
unprivileged container with cgmanager.

Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
Acked-by: Stéphane Graber <stgraber@ubuntu.com>
move bdev_specs struct into lxccontainer.h to allow API users to use it

Signed-off-by: S.Çağlar Onur <caglar@10ur.org>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>