Get rid of jsonschema.compat usage
Get rid of jsonschema.compat usage

jsonschema.compat module is not a public interface anymore and
it got removed in version > 3.2.0
The compat module was a helper for py2/3 compatibility [1].
As Tempest is full py3 now, we can rework the whole
if-condition and let the timeutils to handle any wrong format.

[1] https://github.com/Julian/jsonschema/blob/v3.2.0/jsonschema/compat.py

Closes-Bug: #1946321
Change-Id: Ia78c19c06cfb712b1b8d0aff457fd2f91144dc07

openstack/tempest,openstack/tempest