Fix broken JSON schemas in v2 tests

* The required attribute is not allowed in draft 4 of JSON schema
* The dependency on jsonschema can be relaxed back to all versions

Change-Id: Id0767cfe2fe46d73999563896f851ffb01aa9489
Merge "Fix broken JSON schemas in v2 tests"
Merge remote-tracking branch 'm_src_repo/webob-issue' into build-temp