revert change to retention period - leave default and let user override

[ryandawsonuk]

follow up to #2401

[seldondev]

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[seldondev]

Tue Sep 22 13:30:54 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-2472/1.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2472 --build=1

[seldondev]

Tue Sep 22 13:30:53 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-2472/2.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2472 --build=2

[ryandawsonuk]

/test this

[seldondev]

Tue Sep 22 14:01:17 UTC 2020
The logs for [pr-build] [3] will show after the pipeline context has finished.
https://github.com/SeldonIO/seldon-core/blob/gh-pages/jenkins-x/logs/SeldonIO/seldon-core/PR-2472/3.log

impatient try
jx get build logs SeldonIO/seldon-core/PR-2472 --build=3