nova.tests.unit.test_api_validation.PatternPropertiesTestCase.test_validate_patternProperties_fails fails in 3.6 because py3 check is limited to 3.5

[Chris Dent]

nova.tests.unit.test_api_validation.PatternPropertiesTestCase.test_validate_patternProperties_fails fails in 3.6 because py3 check is limited to 3.5 with:

```
Captured traceback:
~~~~~~~~~~~~~~~~~~~
    b'Traceback (most recent call last):'
    b' File "/Users/cdent/src/nova/nova/api/validation/validators.py", line 300, in validate'
    b' self.validator.validate(*args, **kwargs)'
    b' File "/Users/cdent/src/nova/.tox/py36/lib/python3.6/site-packages/jsonschema/validators.py", line 129, in validate'
    b' for error in self.iter_errors(*args, **kwargs):'
    b' File "/Users/cdent/src/nova/.tox/py36/lib/python3.6/site-packages/jsonschema/validators.py", line 105, in iter_errors'
    b' for error in errors:'
    b' File "/Users/cdent/src/nova/.tox/py36/lib/python3.6/site-packages/jsonschema/_validators.py", line 14, in patternProperties'
    b' if re.search(pattern, k):'
    b' File "/Users/cdent/src/nova/.tox/py36/lib/python3.6/re.py", line 182, in search'
    b' return _compile(pattern, flags).search(string)'
    b'TypeError: expected string or bytes-like object'
```

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/545798

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/545798
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=3017531c82f611b5572079753f7ea3c74c3dd71e
Submitter: Zuul
Branch: master

commit 3017531c82f611b5572079753f7ea3c74c3dd71e
Author: Chris Dent <email address hidden>
Date: Mon Feb 19 11:06:45 2018 +0000

    Fix PatternPropertiesTestCase for py 3.6

    A python version check was only checking for 3.5. As noted
    in the pre-existing comment, an exception message is not a
    particularly stable interface so specific-to-minor-version
    check is maintained.

    Change-Id: I441b90e911fbac033e8cdea96114db22cba96ac5
    Closes-Bug: #1750355

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/nova 18.0.0.0b1 development milestone.