[rql sources] uses an URL as remote host address for pyro/zmq rql sources,
instead of extra configuration parameters. Follows modification of dbapi.connect api.
Closes #2539822
if not rql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',
ask_confirm=False):
rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',
ask_confirm=False)