Description of problem
======================

Package tendrl-ansible contains asserts statements in few places, so that
assumptions can be checked immediately.  The assert tasks contain explanation
of what went wrong, which is presented to the customer if the assert fails.

The problem is that the syntax used here is no longer valid since ansible 2.7,
which makes it fail during execution on the following error:

```
fatal: [localhost]: FAILED! => {"msg": "Incorrect type for fail_msg or msg, expected string and got <type 'list'>"}
```

This affects both prechecks playbook and site.yml playbook (so that it
blocks proper WA installation).

Version-Release
===============

ansible-2.7.0-1.el7ae.noarch
tendrl-ansible-1.6.3-7.el7rhgs.noarc

How reproducible
================

100 %

Steps to Reproduce
==================

1. Install ansible 2.7 from rhel-7-server-ansible-2-rpms channel
2. Install tendrl-ansible
3. Try to run prechecks playbook on any RHGSWA cluster:

```
ansible-playbook -i cluster.hosts prechecks.yml
```

Actual results
==============

Ansible immediately fails on type error for msg of 1st assert statement:

```
# ansible-playbook -i mbukatov-usm1.hosts prechecks.yml

PLAY [localhost] *******************************************************************************************************

TASK [Gathering Facts] *************************************************************************************************
ok: [localhost]

TASK [Check if python dns is installed on ansible control machine] *****************************************************
ok: [localhost]

TASK [Abort the playbook if python dns is not installed] ***************************************************************
fatal: [localhost]: FAILED! => {"msg": "Incorrect type for fail_msg or msg, expected string and got <type 'list'>"}
        to retry, use: --limit @/home/usmqe/prechecks.retry

PLAY RECAP *************************************************************************************************************
localhost                  : ok=2    changed=0    unreachable=0    failed=1 
```

Expected results
================

Ansible continues to run without failing on type error on msg attribute of
assert task.

Additional info
===============

This problem doesn't happen with ansible 2.6 and older.