tests: fix pep8 errors

Commit: a2890d5d614e856a44102d61576a8591a8d2e52f
introduced pep8 and pyflakes errors in tests.
This patch fixes that.

Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1120246
Change-Id: Ieefeb049d295ed89cdfedc7ccc9daee05b7de712
Signed-off-by: Francesco Romani <fromani@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/29960
Reviewed-by: Martin Sivák <msivak@redhat.com>
Reviewed-by: Dan Kenigsberg <danken@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/30073
Tested-by: Martin Sivák <msivak@redhat.com>