Use different trigger phrase and blacklist labels for openshift repos

[vrutkovs]

Openshift project are using PROW bot to run CI tasks. This commit would
unify thier commands - '/retest' to restart tests and don't start tests
if PR has 'needs-ok-to-test' label

I didn't test if this works though, not sure if this is a correct way to override values though

[jlebon]

Thanks for the patch Vadim! Note however that the configurations here are not those that are actually used by the PAPR instance running on the https://github.com/openshift repos. The configs here are for a rework of PAPR running on top of OpenShift (currently in CentOS CI). I'm open to getting a similar patch merged on the active configuration though!

One worry is that it would make interactions less consistent across repos, but consistency within a single repo is more important (though one thing I was pushing for in the past was replacing the PAPR tests in OpenShift to just use the same infra + prow setup as all the other tests -- see https://github.com/openshift/release/issues/732). Mixing PR testing services just complicates things.

[vrutkovs]

I'm open to getting a similar patch merged on the active configuration though!

Awesome, thanks! Could you cc me there (if its public)?

Mixing PR testing services just complicates things.

Yes, agree, but PAPR is important for us until openshift CI and prow would learn how to run Atomic hosts.

In any case, this PR is not critical, just for our convenience - if it breaks something or complicates things too much it should be closed