Сhanges in openstack.yaml are not applied after upgrade Fuel to 9.2

[TatyanaGladysheva]

Detailed bug description:
When we deployed Fuel 9.0, there was default openstack.yaml. Then we performed upgrade, new nailgun was applied, but fixture for openstack.yaml will not be applied because releases with keys already exist. So, changes in openstack.yaml are not applied after upgrade to 9.2.

Steps to reproduce:
1. Deploy Fuel 9.0 RC2 from image (Build 495)
2. Upgrade the fuel master node to 9.2 using instruction https://mirantis.jira.com/wiki/display/QA/MOS+9.1+installation#:
   yum-config-manager --add-repo http://mirror.fuel-infra.org/mos-repos/centos/mos9.0-centos7/snapshots/proposed-2016-12-19-224322/x86_64/
   rpm --import http://mirror.fuel-infra.org/mos-repos/centos/mos9.0-centos7/snapshots/proposed-2016-12-19-224322/RPM-GPG-KEY-mos9.0
   yum install -y python-cudet
   yum clean all
   update-prepare prepare master
   update-prepare update master
3. Change something in /usr/lib/python2.7/site-packages/nailgun/fixtures/openstack.yaml.
For example, I've changed operator_user's name value from 'fueladmin' to 'root' and homedir value from '/home/fueladmin' to '/root'
4. systemctl restart nailgun (maybe extra step)
5. Create cluster with 1 controller, add mos9.0-proposed repo and deploy it
6. After deployment is finished, ssh to controller and check result

Expected results:
Operator_user is root. There is no homedir /home/fueladmin.

Actual result:
Operator_user is still fueladmin. Homedir is /home/fueladmin.

Reproducibility:
100%

Workaround:
DB migration for 9.2 as it was done in https://review.openstack.org/#/c/395496/

Impact:
Any changes in /usr/lib/python2.7/site-packages/nailgun/fixtures/openstack.yaml don't take effect.

Description of the environment:
snapshot #656

Additional information:
Initially this issue was noticed during verification of https://bugs.launchpad.net/fuel/+bug/1634729.

[Alexey Shtokolov (ashtokolov)]

openstack.yaml is a part of fixtures. Nailgun uses it to initialise the release info in DB. All further actions on releases should be performed via API.