3scale provisioning fails if you do not explicitly set eval_app_host variable

[rafaeltuelho]

Description

3scale provisioning fails if you do not explicitly set eval_app_host variable.

Expected Behavior

3scale install step

Actual Behavior

Installation fails with:

TASK [include_role : 3scale] ******************************************************************************************************************************************************************************

TASK [3scale : Prerequisite checks] ***********************************************************************************************************************************************************************
fatal: [127.0.0.1]: FAILED! => {"msg": "The conditional check 'threescale_route_suffix == ''' failed. The error was: error while evaluating conditional (threescale_route_suffix == ''): 'threescale_wildcard_domain' is undefined\n\nThe error appears to have been in '/root/integr8tly/installation/roles/3scale/tasks/prereq-check.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: \"Prerequisite checks\"\n  ^ here\n"}

PLAY RECAP ************************************************************************************************************************************************************************************************
127.0.0.1                  : ok=241  changed=80   unreachable=0    failed=1
master1.tjpe-fef2.internal : ok=4    changed=2    unreachable=0    failed=0

Environment

• Operating system: RHEL 7.6
• OpenShift version: 3.11.104

oc v3.11.104
kubernetes v1.11.0+d4cacc0
features: Basic-Auth GSSAPI Kerberos SPNEGO

Server 
openshift v3.11.104
kubernetes v1.11.0+d4cacc0

• Ansible version:

ansible 2.6.18
  config file = /root/integr8tly/installation/ansible.cfg
  configured module search path = [u'/root/integr8tly/installation/library']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /bin/ansible
  python version = 2.7.5 (default, Jun 11 2019, 12:19:05) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

• Project Version/Tag: release-1.5.0

Steps to reproduce

1. run the install playbook without setting the eval_app_host variable.