Race condition in commands using watch

[akerekes]

Bug report

The wait.Wait.Wait() implementations create the watch they are listen to in a goroutine that can execute later than the code that emits the event the watch was intended for.

Expected behavior

The watch is created upfront, then the wait for the event is executed in a goroutine while the main thread calls the backend that will emit the expected event.

Steps to reproduce the problem

I was able reproduce this by:

• adding 30 seconds sleep into vi/client.go's WatchRevision method before the watch is created on the backend
• call kn revision delete --wait <rev_name>

kn version

HEAD

Knative (serving/eventing) version

N/A