Commit 92c7f629 broke the following scipts:
- lxc-setcap
- lxc-setuid
- lxc-create

This patch adds the missing variables to be substitued by the configure
script.

Cheers.
Signed-off-by: Greg Kurz <gkurz@fr.ibm.com>
Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>