Bug 1904682

Description of problem:

successful-build-config.yaml uses the image busybox from docker.io. As docker.io has rate limits, we should avoid using it in our tests.

Actual results:

https://prow.ci.openshift.org/view/gs/origin-ci-test/pr-logs/pull/openshift_ovn-kubernetes/368/pull-ci-openshift-ovn-kubernetes-master-e2e-vsphere-ovn/1335204821283639296

[sig-builds][Feature:Builds] prune builds based on settings in the buildconfig should prune completed builds based on the successfulBuildsHistoryLimit setting

Dec  5 13:56:46.257: INFO: Running 'oc --namespace=e2e-test-build-pruning-b42xg --kubeconfig=/tmp/configfile162613505 logs -f build.build.openshift.io/myphp-1 --timestamps --v 10'
Dec  5 13:56:46.630: INFO: 2020-12-05T13:54:50.023953860Z Caching blobs under "/var/cache/blobs".
2020-12-05T13:54:50.038965713Z 
2020-12-05T13:54:50.038965713Z Pulling image busybox ...
2020-12-05T13:55:22.236024839Z Warning: Pull failed, retrying in 5s ...
2020-12-05T13:55:59.308692134Z Warning: Pull failed, retrying in 5s ...
2020-12-05T13:56:36.419216205Z Warning: Pull failed, retrying in 5s ...
2020-12-05T13:56:41.488929271Z error: build error: failed to pull image: After retrying 2 times, Pull image still failed due to error: while pulling "docker://busybox" as "busybox": Error initializing source docker://busybox:latest: Error reading manifest latest in docker.io/library/busybox: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit

Additional info:

https://search.ci.openshift.org/?search=failed%3A.*should+prune+completed+builds+based+on+the+successfulBuildsHistoryLimit+setting&maxAge=48h&context=1&type=build-log&name=master-e2e&maxMatches=5&maxBytes=20971520&groupBy=job

This file is also used by

[sig-instrumentation][sig-builds][Feature:Builds] Prometheus when installed on the cluster should start and expose a secured proxy and verify build metrics

https://search.ci.openshift.org/?search=failed%3A.*should+start+and+expose+a+secured+proxy+and+verify+build+metrics&maxAge=48h&context=1&type=build-log&name=master-e2e&maxMatches=5&maxBytes=20971520&groupBy=job