openstack: ensure HOME environment variable
openstack: ensure HOME environment variable

Make it so even after a reboot and run from root, the HOME is set to the
user directory where the scripts are expected to be.

Signed-off-by: Loic Dachary <b6eae37fc74638590e3f9030895d42446505d41b@dachary.org>

SUSE/teuthology,dmick/teuthology,SUSE/teuthology,dmick/teuthology,ceph/teuthology,dreamhost/teuthology,caibo2014/teuthology,ceph/teuthology,ktdreyer/teuthology,ktdreyer/teuthology,SUSE/teuthology,robbat2/teuthology,caibo2014/teuthology,robbat2/teuthology,dmick/teuthology,dreamhost/teuthology