1.2.4: BUGFIX: saveInto() was not working as expected for UnsavedRelationList

Most commonly seen in frontend forms -- if the form was not bound to a record (e.g. `loadDataFrom()`), the `getRelation()` method was returning false no matter what, because it relied on `$form->getRecord()`. In the `saveInto($record)` method, it is critical that `getRelation()` is explicitly passed the record it is checking, rather than relying on the precondition of the form being bound to a record.