[rql rewrite] may_be_shared_with should consider relation's scope (closes #3024730) When a relation's scope is not the current statement, it must not be shared (instead of comparing the statement).

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