Commit 5c13765168 removed postgre registration triggerd
by the automatic gofmt command but it was the only where pg is registered. This commit
fixes behavior and adds unit tests to check whether postgre & sql are registered or not.
A bug concerning the validation of connectionString is found,
however there is no solution to fix it for now, postgresql API
doesn't help to do that hence disabling validation of that field.
Anis Elleuch