[etwist] pass the repository to the root resource This is another step toward a cleaner instantiation scheme for the repo. The http test now pass an already created object to the etwist server instead of relying on the config cache. Related to #2249513

if not rql('CWConstraintType X WHERE X name "RQLUniqueConstraint"',
           ask_confirm=False):
    rql('INSERT CWConstraintType X: X name "RQLUniqueConstraint"',
        ask_confirm=False)