If an outbound Cloud Agent become disconnected and is using the OnceRetentionStrategy it will never attempt to reconnect.

Steps to reproduce

• create a Cloud using Google Cloud Engine
• set the cloud One-Shot to enabled
• create a pipeline job using the node to execute `sh 'sleep 240'`
• start the job
• wait for the node to be provisioned and terminate the `agent.jar` process

Expected Outcome

• Jenkins detects the agent is disconnected and attempts to relaunch it
• job continues successfully to completion

Actual

• Jenkins detects the agent is disconnected but does not attempt to relaunch it.
• Job stays in limbo land.