Detect prototyping bug where gateway node does not have correct db config

In the current prototyping code, there is an issue where one db doesn't correctly pull the latest db config from metakv.  This seems like something that should be testable via a unit test framework.

Steps to reproduce:

• Add general and listener config to metakv
• Add db config to metakv
• Start sg / RestTester
• Go to admin _config endpoint, and check to see if db is included in list of databases

Expected: db is included

Actual: db not included – fail