Ansible: add better error message when ansible_become_pass is missing

[Bart Wensley]

Brief Description
-----------------
When an ansible playbook is applied and the following are true:
1. The wrsroot password is not set to the default St8rlingX* password.
2. The ansible_become_pass option is not specified.

The playbook apply fails with this error: "Host localhost does not have the right image!"

This is not intuitive and doesn't indicate the cause of the error.

Severity
--------
Minor

Steps to Reproduce
------------------
See above

Expected Behavior
------------------
The error message should indicate the cause of the problem. Also note that if the playbook apply is done with sudo permissions the error does not occur. Even if sudo is used, the playbook should probably still fail with an indication that there is a password mismatch issue.

Actual Behavior
----------------
See above

Reproducibility
---------------
Reproducible

System Configuration
--------------------
Any

Branch/Pull Time/Commit
-----------------------
Designer load built on June 4, 2019.

Last Pass
---------
Never

Timestamp/Logs
--------------
N/A

Test Activity
-------------
Developer testing

[Ghada Khalil (gkhalil)]

Low priority; inaccurate error msg. Would be nice to fix, but not considered gating.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/664759
Committed: https://git.openstack.org/cgit/starlingx/config/commit/?id=58bf3c849af370d5aaef6967bb660055099f3fe0
Submitter: Zuul
Branch: master

commit 58bf3c849af370d5aaef6967bb660055099f3fe0
Author: Tee Ngo <email address hidden>
Date: Tue Jun 11 22:01:08 2019 -0400

    Assistive error msg when sudo passwd is incorrect

    The error message when ansible_become_pass does not match with the
    password of the Ansible user of the bootstrap playbook is misleading.
    This commit corrects that.

    Closes-Bug: 1832389
    Change-Id: I298370cc4e52d80dee630894fc1cb2a2c40337b3
    Signed-off-by: Tee Ngo <email address hidden>