This has a cherry-pick of #300 and fixes e2e unhandled errors
RolloutBlocks frequently take a little bit to propagate to Shipper's
informers, making tests fail for no good reason. Since we have found no
way to verify that they have propagated, we use the good ol' sleep as
the second best thing.
Hopefully this will fix the recent flaky e2e tests that have been plaguing us.
This has a cherry-pick of #300 and fixes e2e unhandled errors