BZ #1134139 - Track Real User behind SSH logins

The assumption here is that OpenShift controls the authorized keys and so can guarantee that it will manage the OPENSHIFT_LOGIN value will be set correctly. There is a potential edge case after this patch is applied, but before the authorized_keys file is updated where a user might be able to hack the value using "rhc env set". If that works, all that happens is that there's a bogus value in the audit trail.