Fix validation error DTO path property

[davidkopp]

The property path is of the validation error DTO is null.

Request:

curl -X PUT \
  http://localhost:8080/applications/realworld/v0.0.1/deploymentInformation/react-redux-realworld-example-app \
  -d '{
    "replicas": 0
}'

Response:

{
    "status": 422,
    "error": "Unprocessable Entity",
    "message": "Validation Error",
    "fieldErrors": [
        "Field 'replicas' must be at least one replica"
    ],
    "path": null
}