Revert "Fix variable interpolation for suffix addition to service usernames"

This reverts commit 0679242fe9c5d276ff2f71b6ffaa85c85150afd2.
Revert "Fix typo. Forgot ','"

This reverts commit 8d2cf0e6f2afb9b501094b5e349285bebed2b259.
Revert "Change default keystone username for services to 'servicename_sys'"

This reverts commit 3a919e428c1d36d3479234b65ea8c02e9ba4f2a7.
Revert "Change default keystone username for neutron service to 'neutron_sys'"

This reverts commit 5f1480e50ae3fe339ba95a2d3d521006a27b4580.