remove reference to kafka chart

[gsunner]

What this PR does / why we need it:
Fix a bug in the helm charts build/publishing makefile

Which issue(s) this PR fixes:
Fixes #2502

Special notes for your reviewer:
none

Does this PR introduce a user-facing change?:

NONE

[seldondev]

Fri Oct 2 10:36:10 UTC 2020
The logs for [lint] [2] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2516/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2516 --build=2

[seldondev]

Fri Oct 2 10:36:19 UTC 2020
The logs for [pr-build] [1] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2516/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2516 --build=1

[gsunner]

/approve

[seldondev]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gsunner

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