Sensor disappears when added to a DB

[csdillard]

If you add a sensor driver to a database (without restarting the sensor or database), it disappears from the node's web service interfaces. It is no longer listed in the SOS Service's test links, nor is it listed in the SWE API list of systems.

Here are the steps to reproduce:

Setup:

• Start with a blank OSH node. Log in to the admin console.
• Go to the Databases panel. Add a new System Driver database, configure it with an H2 Historical Obs Database, and then start the database.
• Go to the Sensors panel. Add a new UasOnDemandSensor. Start the sensor. (It's not clear to me whether the actual sensor matters. It may be important that this particular sensor will never emit observations.)
• Confirm that the system shows up in the SOS Service Test Links tab.

Cause the bug:

• Go back to the Databases panel.
• Click the "+" to add the "New UasOnDemandSensor" to the System Driver database you created above.
• Click Apply Changes.
• Observe that the system is now missing from SOS Service test links. It is also missing from the SWE API list of systems (if that is enabled on your node).

Since restarting the sensor "fixes" the issue, I'd say this is a minor bug.