Jenkins CI plugin no longer works with internal CA SSL hosts

This issue is quite similar to https://gitlab.com/gitlab-org/gitlab-ce/issues/2681 however it just popped up in 8.9.0 where the workaround (putting the CA cert in /opt/gitlab/embedded/ssl/certs) no longer worked so tried setting things up according to http://docs.gitlab.com/omnibus/common_installation_problems/README.html#using-self-signed-certificate-or-custom-certificate-authorities however while that works for the Jenkins CI (Deprecated) plugin (as I see no errors when doing the test) it doesn't work with the Jenkins CI plugin at all which simply spits out:

We tried to send a request to the provided URL but an error occurred: SSL_connect returned=1 errno=0 state=error: certificate verify failed

I set this in gitlab.rb as per the instructions:

gitlab_shell['http_settings'] = { user: 'username', password: 'password', ca_file: '/etc/ssl/certs/ca-bundle.crt', ca_path: '/etc/pki/tls/certs', self_signed_cert: true}

But it makes no difference. Tested connecting to the jenkins server using /opt/gitlab/embedded/bin/curl and it doesn't complain about an unknown/invalid cert at all.

Things worked great until 8.9.0 and now this is broken. In the gitlab-rails/production.log I see:

Started GET "/devops/sfm2/services/jenkins/test" for 127.0.0.1 at 2016-06-27 11:28:28 -0400
Processing by Projects::ServicesController#test as HTML
  Parameters: {"namespace_id"=>"devops", "project_id"=>"sfm2", "id"=>"jenkins"}
WebHook Error => SSL_connect returned=1 errno=0 state=error: certificate verify failed

This is an urgent problem for us so if you need anything please let me know. It's possible I configured something wrong but if so, I have no idea what it might be. Thank you.