Description of problem:
QE have to test nightly build before we release OCP to customers, but openshift ansible gets the wrong OCP version.

Ansible (/usr/share/ansible/openshift-ansible/playbooks/scaleup.yml) gets the OCP version as following:

# cat openshift-ansible/roles/openshift_node/defaults/main.yml
openshift_node_packages:
  - openshift-clients{{ l_cluster_version }}
  - openshift-hyperkube{{ l_cluster_version }} 

# cat openshift-ansible/roles/openshift_node/tasks/install.yml
- name: Get cluster version
  command: >
    oc get clusterversion
  register: oc_get

- name: Set fact l_cluster_version
  set_fact:
    l_cluster_version: "-{{ oc_get.stdout | regex_search('^\\d+\\.\\d+\\.\\d+') }}"

For example when testing 4.2.0-0.nightly-2019-10-28-140411, we will get the this:
TASK [openshift_node : Install openshift packages] *****************************
Wednesday 30 October 2019  00:27:52 +0800 (0:00:00.057)       0:03:40.003 ***** 

changed: [10.0.32.5] => {"ansible_job_id": "183378387509.16194", "attempts": 1, "changed": true, "changes": {"installed": ["cri-o", "openshift-clients-4.2.0", "openshift-hyperkube-4.2.0"], 

But 4.2.0-0.nightly-2019-10-28-140411 is the same as stable v4.2.2 
# oc image info registry.svc.ci.openshift.org/ocp/release:4.2.0-0.nightly-2019-10-28-140411 |grep BUILD_VERSION
BUILD_VERSION=v4.2.2

This will be potential a problem in the feature for QE testing.

So, QE want an ansible variable that can be assigned the OCP version.  


Version-Release number of the following components:
# rpm -q openshift-ansible
openshift-ansible-4.2.0-201910111434.git.190.85c9108.el7

# rpm -q ansible
ansible-2.8.6-1.el7ae.noarch

# ansible --version
ansible 2.8.6
  config file = /etc/ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, Mar 26 2019, 22:13:06) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

How reproducible:
Always

Steps to Reproduce:
1. Scale up RHEL node in OCP4
2.
3.

Actual results:
Only get the nightly version then install the wrong package.

Expected results:
Install the correct package with nightly build

Additional info:
Please attach logs from ansible-playbook with the -vvv flag