Improve ODL websocket backend haproxy check

[Tim Rozet]

Currently the healthcheck for ODL websocket simply checks the port is open. We have hit issues in ODL where hte port is open, but websocket is actually not available on one or more controllers. We can improve this healthcheck to actually check if we can open a websocket connection.

[Alex Schultz (alex-schultz)]

This bug has had a related patch abandoned and has been automatically un-assigned due to inactivity. Please re-assign yourself if you are continuing work or adjust the state as appropriate if it is no longer valid.

[OpenStack Infra (hudson-openstack)]

Change abandoned by Alex Schultz (<email address hidden>) on branch: master
Review: https://review.opendev.org/612794
Reason: This review is > 90 days without comment, and failed Zuul the last time it was checked. We are abandoning this for now. Feel free to reactivate the review by pressing the restore button and leaving a 'recheck' comment to get fresh test results. For more details check policy https://specs.openstack.org/openstack/tripleo-specs/specs/policy/patch-abandonment.html

[Brent Eagles (beagles)]

ODL has been removed from the tht repo. Closing.