Uncaught exception 'PropelException' with message 'Call to undefined method: setByName' in Xx on line YY

When querying for a model using `findOneOrCreate()` the ModelCriteria calls `BaseObject->setByName()` when a object needs to be created.
This method is only created by the generator when `propel.addGenericMutators=true` is defined.

The exception thrown when `propel.addGenericMutators=false` looks like the following:
Fatal error: Uncaught exception 'PropelException' with message 'Call to undefined method: setByName' in Xx on line YY

this exception is confusing because it is not obvious that propel internals for this api need the flag to be true and the error message doesn't give a hint into the right direction...

Example Query:

```php
    $content = ContentQuery::create()
        ->filterByIdentification('extension_point')
        ->filterByValue1($extension['extension_point'])
        ->findOneOrCreate();
```
produces the exception mentioned above.

should we improve things here?

moved from https://mail.google.com/mail/?shva=1#inbox/13db16040a2789fd