hard coded platform release in ansible

[Scott Little]

Brief Description
-----------------

The file cgcs-root/stx/ansible-playbooks/playbookconfig/src/playbooks/roles/bootstrap/prepare-env/vars/main.yml contains a hard coded value for the platform release value.

 ...
 supported_release_versions:
   - "19.12"
 ...

This can cause uninstallable loads if the platform release value is changed and a matching change is not sourced in the above file.

Ideally we should only have to change the platform release value in one place and all other files pick up the change at build time.

The single point of change should be the file cgcs-root/stx/utilities/utilities/build-info/release-info.inc. It a bash freindly, and contains ... e.g. ...

 PLATFORM_RELEASE="19.12"

One way to pick this up would be via sed substitution. e.g. file contains ...

 ...
 supported_release_versions:
   - "<<PLATFORM_RELEASE>>"
 ...

and build performs the sed substitution like this ...

 source $MY_REPO/stx/utilities/utilities/build-info/release-info.inc
 cat prototype_file | sed "s/<<PLATFORM_RELEASE>>/${PLATFORM_RELEASE}/" > final_file

Severity
--------
Critical: uninstallable

Steps to Reproduce
------------------
 Change PLATFORM_RELEASE value in cgcs-root/stx/utilities/utilities/build-info/release-info.inc
 build
 intall

Expected Behavior
------------------
install successfully

Actual Behavior
----------------
Install failes on mismatched PLATFORM_RELEASE value

Reproducibility
---------------
100%

System Configuration
--------------------
N/A

Branch/Pull Time/Commit
-----------------------
CENGN build at time stamp 20191203T000000Z

Last Pass
---------
20191202T000000Z

Timestamp/Logs
--------------
20191203T000000Z

Test Activity
-------------
Install

[Ghada Khalil (gkhalil)]

stx.4.0 / medium priority - this is more of an improvement to make release prep easier

[Ghada Khalil (gkhalil)]

Lowering the priority - this is a would-be-nice enhancement to the build system, but will not hold up stx.4.0. Until implemented, the release will be updated manually.

This has already been done for stx.4.0:
https://review.opendev.org/#/c/730113/