Fix the DB unit tests.
Fix the DB unit tests.

This fixes an issue where the tap runner would exit early because
the tests weren't registered until the `DB.connect()` handler was
called.

jrgm/fxa-auth-server,shane-tomlinson/fxa-auth-server,jrgm/fxa-auth-server,chilts/fxa-auth-server,mozilla/fxa-auth-server,TDA/fxa-auth-server,chilts/fxa-auth-server,eoger/fxa-auth-server,chilts/fxa-auth-server,eoger/fxa-auth-server,TDA/fxa-auth-server,jrgm/fxa-auth-server,shane-tomlinson/fxa-auth-server,mozilla/fxa-auth-server,shane-tomlinson/fxa-auth-server,dannycoates/picl-idp,eoger/fxa-auth-server,TDA/fxa-auth-server,dannycoates/picl-idp,TDA/fxa-auth-server,dannycoates/picl-idp,mozilla/fxa-auth-server,eoger/fxa-auth-server,jrgm/fxa-auth-server,dannycoates/picl-idp,mozilla/fxa-auth-server,shane-tomlinson/fxa-auth-server,chilts/fxa-auth-server