Fix hardcoding of vagrant username

Racksapce and other cloud providers don't use a vagrant username, which
will cause the autoInstaller script to throw errors and not perform the
intended actions.

Change-Id: Ie9d0aaaa1b4aa04b3a85c8662b2e27c2cc9ac5f4
OSEHRA-Id: http://issues.osehra.org/browse/VAF-147