neo4j combined with hibernate domain objects not persisted to neo4j

### Steps to Reproduce

1. Create a new project using both neo4j and hibernate using Grails 3.3.2. Following the documentation here: http://gorm.grails.org/latest/neo4j/manual/#combiningNeo4jAndHibernate
2. Using mapWith="neo4j" to assign a domain class to neo4j
3. Save domain and logs return true
4. Check neo4j. Object is never persisted

### Expected Behaviour

Domain object should be saved to neo4j

### Actual Behaviour

Domain object is not saved to neo4j. But can save to postgresql through hibernate when removing the mapWith property. When removing all references to hibernate, and using neo4j standalone, it works as expected and domain objects can be saved in this case.

### Environment Information

- **Operating System**: Windows 10
- **GORM Version:**
- **Grails Version (if using Grails):** 3.3.2
- **JDK Version:** 1.8.0_161
- **Hibernate version:** 5.1.5.Final

Start with the combining Neo4j and Hibernate section of the GORM guide and reproduce the Grails 3.3.2 setup using mapWith="neo4j". Compare persistence with Hibernate enabled and disabled; done means the domain object is present in Neo4j after save while the PostgreSQL path remains distinguishable.

Written by the indexing model from the issue text.