cgroups: don't escape if we're not real root
cgroups: don't escape if we're not real root

If we're host unpriv but root in our userns, we can't really escape
cgroups. Let's switch the cgroup escape test to reflect this.

Signed-off-by: Tycho Andersen <6b523322678240882acbb4da5312a12d8cd0082d@tycho.ws>

ss1h2a3tw/lxc,thmo/lxc,caglar10ur/lxc,hallyn/lxc,ss1h2a3tw/lxc,ss1h2a3tw/lxc,caglar10ur/lxc,hallyn/lxc,thmo/lxc,thmo/lxc,caglar10ur/lxc,hallyn/lxc