If a workbook definition validation fails, it is still in the DB

[Nikolay Makhotkin]

Steps to reproduce:

1. Create workbook with broken definition or upload definition in existing workbook

  mistral workbook-create wb desc tag workbook.yaml
OR
  mistral workbook-upload definition wb workbook.yaml

2. Client or REST API answers that definition is broken
3. Check workbook-definition

  mistral workbook-get-definition wb

4. Got broken workbook definition in the DB

Possible solution:
  Delete workbook definition if workbook validation fails