A subtlety about the engine is that while it guarantees CheckApply
happens in the listed edge-based dependency order, it doesn't stop
Watch from starting up in whatever order it wants to. As a result, we
can prematurely error since the docker service isn't running yet. It may
in fact be in the process of getting installed and started by mgmt
before we then try and use this resource! As a result, let it error once
for free and wait for CheckApply to get going before we start again.
Keep in mind, Watch has to use the .Running() method once to tell
CheckApply to do its initial event. So this concurrency is complex!
It's unclear if this is a bug in mgmt or not, but I'm leaning towards
not, particularly since there isn't an obvious way to fix it.
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