Don't override default value of config option sqlite_db
Don't override default value of config option sqlite_db

This is follow up of aa3d521492233147612920ec4722552454ec40c8,
we removed usage of sqlite_db in that commit, but forget to
remove code of overriding its default value.

Change-Id: I9692c71ea014ceff681ec56b68fc2f7db87f5a4c

openstack/smaug,openstack/smaug