Adds pre_task to checks to address Issue #178

[vvaldez]

What does this PR do?

Addresses Issue #178 by adding a pre_task check for openshift_ansible_path directory and openshift_ansible_playbook file and will halt the playbook if not found or accessible before any provisioning. Also adds the following to support this feature:

• Adds default variables for openshift_ansible_path and openshift_ansible_playbook
• Checks for accessible path and playbook in pre_task before any provisioning
• Adds these variables to inventory file
• Modifies provision.sh to read these variables from inventory file
• Adds parameter to override these varibles in provision.sh

  How should this be manually tested?

Run ose-provision.yml on a system without the default path of /usr/share/ansible/openshift-ansible or the playbooks/byo/config.yml to ensure the playbook fails. Also attempt specifying a custom path and/or playbook in an inventory or variables file.

Is there a relevant Issue open for this?

None.

Who would you like to review this?

/cc @oybed @etsauer @sabre1041

[etsauer]

@vvaldez why should ose-provision.yml care about the path to openshift-ansible? it doesn't ever call anything in openshift-ansible. the openshift-ansible/playbooks/byo/config.yml is called externally by the wrapper script.

[etsauer]

I'm going to close this as it doesn't seem to apply since we pulled the tie together of openshift-ansible out to a script.