blocked state remains after setting mongodb_uri

[Paul Collins]

By design, status-set blocked followed by status-set active does not clear blocked until the next hook is run.

This happens because install_prometheus_mongodb_exporter is called before maybe_monitor_juju_db, which is what triggers the chain of events that results in install_prometheus_mongodb_exporter being called a second time and setting active, which is then too late.

The blocked state is cleared on the next run of the update-status hook, so this isn't the end of the world.

[Paul Collins (pjdc)]

This description is not correct -- in fact, install_prometheus_mongodb doesn't get called again until the next time a hook runs.