Deployment of a sub-chart that only contains hooks is failing

Deployment of a sub-chart that only contains hooks is failing: the Release is set to FAILED (at least on the first install) and `helm spray` exists with error code 1 and message:
```
Error: no objects visited
Error: plugin "spray" exited with error
```

This is due to a known bug in helm: https://github.com/helm/helm/issues/4670 