Fix python3 compatibility for RHEL8
The fix in https://pagure.io/sigul/pull-request/16 does not work for
RHEL8, because the six module shipped by RHEL8 is somewhat ancient.
Instead, do the same thing six.ensure_text() does, just manually.
Tested on C8S and F35 and works on both.
Signed-off-by: Ralf Ertzinger <ralf@skytale.net>