BZ #1134139 - Track Real User behind SSH logins

This prefix would cause problems if the username included a space, or in various other semi-plausible scenarios.

Say login="John Doe".

Then the command becomes:
    OPENSHIFT_LOGIN=John Doe usr/bin/oo-trap-user[...]

I.e. "Doe" becomes the command instead of oo-trap-user.

You could put quotes around it, but then if a user name includes quotes, you could have problems... so really, the whole thing needs to be shell-escaped.