Remove extraneous op_code handling for relations

This PR resolves issue https://jira.ez.no/browse/EZP-20239

```op_code``` handling for relations in Legacy Stack is extraneous and has to be removed in order to allow ```op_code``` handling in Legacy Storage engine.
Presumably ```op_code``` was deprecated by providing complete ```LINK``` and ```EMBED``` relation type data in ```eZContentObject::$InputRelationList```, but for some reason was never removed.

Additionally this fixes a bug where version number 1 was not recognized as draft.

See linked issue for more details.