[libvirt] Add UID/GID support to virt-sandbox-service

This patch set is adding support for UID/GID/USERNAME/USERDIR for use with openshift containers Also fixes virt-sandbox-service to not complain if the destdir has been precreated. Finally we also do not want excess processes running withing containers (/bin/sh). [sandbox PATCH 1/3] Add UID/GID support for use with interactive [sandbox PATCH 2/3] Only create the destination path if it does not [sandbox PATCH 3/3] Do not run a shell within a lxc container by