acceptance: update how we build the python compose image

[rickystewart]

Up until this point we were using apt install postgresql-client to
install the psql binary in this image. Because the postgresql-client
apt package was apparently updated to a later version of postgres
last week that includes this change,
the TestComposeGSSPython acceptance test started failing with the
following error:

psql: error: private key file "/certs/client.root.key" must be owned by the current user or root

Less recent versions of psql are more permissive about cert
permissions, so we work around this by simply copying a less recent
version of psql from the older postgres:11 image.

Release note: None
Release justification: Test-only change

[cockroach-teamcity]

This change is 

[otan]

thanks for looking into this!!!

[otan]

hmm, looks like it's failing with

        python_1     | Creating a k5s token...
        kdc_1        | krb5kdc: starting...
        python_1     | Password for [email protected]: 
        python_1     | Creating test user
        python_1     | Error: You must install at least one postgresql-client-<version> package

[rickystewart]

Yep, I think I'll have to do a couple more iterations on this. 🙄 Very annoying. Stay tuned.

[rickystewart]

bors r=otan

[craig]

Build succeeded:

• GitHub CI (Cockroach)

[blathers-crl]

Encountered an error creating backports. Some common things that can go wrong:

1. The backport branch might have already existed.
2. There was a merge conflict.
3. The backport branch contained merge commits.

You might need to create your backport manually using the backport tool.

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error creating merge commit from ecf90bc to blathers/backport-release-21.1-81313: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 21.1.x failed. See errors above.

---

error creating merge commit from ecf90bc to blathers/backport-release-21.2-81313: POST https://api.github.com/repos/cockroachdb/cockroach/merges: 409 Merge conflict []

you may need to manually resolve merge conflicts with the backport tool.

Backport to branch 21.2.x failed. See errors above.

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_{🦉 Hoot! I am a Blathers, a bot for CockroachDB. My owner is otan.}