[rql rewrite] backout 7177:f2a976cf7dac : since EXISTS is the variable scope, we want to insert snippets here anyway (other solution would be to NOT insert snippets at all in such case). Closes #1625464

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