[libvirt] This patch mounts tmpfs on /run iff /run directory exists in libvirt-lxc containers.

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 We do not want to share /run with containers in order to prevent information leakage and applications within the containers attempting to communicate with applications outside of the container. It uses the same mount options used for /dev. We also want to bind mount over /var/run directory since this will either be a symbolic link to /run but on some installations /run is bind mounted over /var/run. If we just mount /run we are not guaranteed the /var/run will have the same content.