cg: allow properties that aren't integers

In particular, cpuset.cpus and cpuset.mems can both be "lists" (strings), as
well as hex integers. We don't use the result of this parse, so it is fine to delete it.

Signed-off-by: Tycho Andersen <tycho.andersen@canonical.com>
Signed-off-by: Pavel Emelyanov <xemul@parallels.com>