gate-nova-python27 fails with "RuntimeError: maximum recursion depth exceeded"

[Tony Breeds]

Review: https://review.openstack.org/#/c/194325/ failed with $subject

Logstash:
http://logstash.openstack.org/#eyJzZWFyY2giOiJtZXNzYWdlOlwiUnVudGltZUVycm9yOiBtYXhpbXVtIHJlY3Vyc2lvbiBkZXB0aCBleGNlZWRlZFwiIEFORCB0YWdzOlwiY29uc29sZVwiIEFORCBidWlsZF9xdWV1ZTpcImdhdGVcIiBBTkQgYnVpbGRfbmFtZTpcImdhdGUtbm92YS1weXRob24yN1wiIiwiZmllbGRzIjpbXSwib2Zmc2V0IjowLCJ0aW1lZnJhbWUiOiI2MDQ4MDAiLCJncmFwaG1vZGUiOiJjb3VudCIsInRpbWUiOnsidXNlcl9pbnRlcnZhbCI6MH0sInN0YW1wIjoxNDM1NzE1Njg3MDU0LCJtb2RlIjoiIiwiYW5hbHl6ZV9maWVsZCI6IiJ9

Possibly related to: https://review.openstack.org/#/c/197176

[Matt Riedemann (mriedem)]

It was introduced by this change:

https://review.openstack.org/#/c/197176/

And actually the error shows up in the gate queue on patch set 2 of that change but for some reason Jenkins didn't fail so it was merged and now we have it intermittently failing.

[Matt Riedemann (mriedem)]

This is probably a better query since it's not filtering on the gate queue:

http://logstash.openstack.org/#eyJmaWVsZHMiOltdLCJzZWFyY2giOiJtZXNzYWdlOlwiTWF4aW11bSByZWN1cnNpb24gZGVwdGggZXhjZWVkZWRcIiBBTkQgdGFnczpcImNvbnNvbGVcIiBBTkQgYnVpbGRfbmFtZTpcImdhdGUtbm92YS1weXRob24yN1wiIiwidGltZWZyYW1lIjoiNjA0ODAwIiwiZ3JhcGhtb2RlIjoiY291bnQiLCJvZmZzZXQiOjAsInRpbWUiOnsidXNlcl9pbnRlcnZhbCI6MH0sInN0YW1wIjoxNDM1NzU5NjMxNzgyfQ==

[Matt Riedemann (mriedem)]

e-r query: https://review.openstack.org/#/c/197602/