Bad output when scaling Deployment to zero

[KnVerey]

The Deployment was in fact successfully scaled to zero. The zero-replica integration test deploys zero replicas to begin with; we need one that deploys 1 and then scales to 0 in a second deploy.

[peiranliushop]

The originally reported error log could not be reproduced although scale down was successful. A test is added in PR #224
If the error logs appear again in future, the test should be able to catch it, then we can reopen the issue.
I will close the issue.