CentOS 7

Just checked that building pymcsapi with Python 3.6 instead of Python 3.4 is enough to change pymcsapi's Python 3 dependency in CentOS 7.
The test pipelines passed from the 1.1.8, 1.2.5, and 1.4.0 branches against ColumnStore 1.2.3 on my build environment.
I updated the built instructions in GitHub's README.md in the regarding branches.

It is mainly using python36-devel instead of python34-devel.
Further to note is, that all pip3 test dependencies need to be reinstalled in order to get the test pipeline working.
I further validated in my test environment that the built rpms state the correct Python 3.6 dependency and are install and usable.

In order to make this change effective, we have to change our buildbot build pipeline for CentOS 7 to use Python 3.6 (once CS 1.2.4 is released)

I'll therefore forward the ticket to ben.thompson to make the regarding changes in buildbot.
Once he is done, he can issue the pull requests for the linked branches MCOL-3331, MCOL-3331-upmerge-into-1.2, and MCOL-3331-upmerge-into-1.4.

For QA:
Once Ben made his changes and buildbot ran, verify:

• that all mcsapi related tests in our buildbot test pipeline succeed
• that the build CentOS 7 pymcsapi3 and pyspark3 packages state Python 3.6 as dependency
• that Python 3.6 is resolved automatically as dependency when pymcsapi3 or pyspark3 is installed through our package repositories on CentOS 7

I think this ticket got left in limbo and has been resolved for a while. centos7 builds are using python 3.6

Build verified: 1.4.1-1 source

[root@localhost api]# git show
commit 10c5ea531a20c54f4fffe45b9558fa86f70b6b4b
Merge: 262a726 d7c70a5
Author: Andrew Hutchings <andrew@linuxjedi.co.uk>
Date: Wed Oct 16 09:27:00 2019 +0100

Merge pull request #164 from mariadb-corporation/fix-testing

Make C++ regression suite work

Verified that it is now using python 3.6