`swarm stats all` requires that the ResourceManager instance
implements `rcmgr.ResourceManagerState`, and `loggingResourceManager`
was not implementing it, so the command was failing.
Also added a sharness test to check that the command is executing
correctly, because `jq -e` doesn't return an error if the json is nil.
Signed-off-by: Antonio Navarro Perez <antnavper@gmail.com>
This periodically logs how many times Resource Manager limits were
exceeded. If they aren't exceeded, then nothing is logged. The log
levels are at ERROR log level so that they are shown by default.
The motivation is so that users know when they have exceeded resource
manager limits. To find what is exceeding the limits, they'll need to
turn on debug logging and inspect the errors being logged. This could
collect the specific limits being reached, but that's more complicated
to implement and could result in much longer log messages.
