Description of problem:
If the user accidentally deselects the project-version from the list in a request to join group action, the resul is a mere notification on the project languages list
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Sign in as a project maintainer
2. Go to a project version, click the Request to add project to group
3. Select any group
4. Deselect the item in the list at the top of the page
5. Press Send Message
Goes back to the project version page, with "No project version selected." at the top
Should be on the same request page, with an appropriate error.
Verified at 29de4991b655f8742b35b78d2508da6d8119f41d
Closing VERIFIED bugs for Zanata server 3.3.2.