Synchronization problem when quickly restarting KER in distributed-mode

[bnouwt]

This problem can be reproduced with the following setup and scenario:

Start the following applications:

• Knowledge Directory (KD)
• KER-A
• KER-B

Restart the KER-B quickly (before the KD noticing its absence) and immediately (before it discovers new peers) add a SC. This should result in the messsage:
• Notifying 0 peer(s) of new or removed Smart Connectors, there are now 1 smart connectors

KER-B will never notice the new SC that was created in VUKER and ignores any messages received from this SC.

The work around is to shutdown KER-B and keep it off for 5 minutes, so that KER-A notices its absence. Then start KER-B again and it will function correctly.

Two parts of fixing this problem:

1. Make sure graceful shutdown is implemented better in the KER. For example, when the RemoteKerConnectionManager stops, send a shutdown message by calling the RemoteKerConnection.stop() method. Also make sure a JVM shutdown hook is implemented to stop the Message Dispatcher and gracefully SmartConnectorImpl.stop() all smart connectors in the KER.
2. When a KER discovers a new peer (KER) it sends its runtimedetails to this KER, just to be sure that it gets an update when it is restarted. This might be a duplicate action in normal circumstances, but when it quickly restart the other KER just did not notice yet and will not take action to update its information about the KER.