Editing a database server's config removes the index information

Steps to reproduce:

1. Create a database server.
2. Put one or more indexes on that database server.
3. Edit the database server settings (e.g., change the name or the "Minimum character count" setting).
4. The information about indexes on the server will have been removed from the server, searches and indexing will throw exceptions.

Should be simple to fix, we just need to combine the new options with the old information upon saving (submitConfigurationForm()).