db: use new functionality in 0000_config.sql

Changes 0000_config.sql to use the new function, this simplifies teh
configuration settings code and makes it more maintainable.

Change-Id: I52e4c5b2b63650722e902c3bcca5e60cc5a88793
Signed-off-by: Eli Mesika <emesika@redhat.com>