Incremental update broken for puppet modules
Description of problem:
HTTP 500 server error when calling the incremental update.
Steps to Reproduce:
This is found in automation with the following steps:
1. Create and publish CV with some content
2. Create composite CV, add previously created CV inside it
3. Publish composite CV
4. Create a puppet repo and upload a puppet module into it
5. Incrementally update the CVV with the puppet module with 'propagate_all_composites' flag set to 'True'
Successful API call.
HTTP 500 to server