Workflow owners do not necessarily have access to their workflows: user comparison fails

Steps to reproduce:
1. Create a user in the admin UI
2. Create a group with all the available roles except ROLE_ADMIN and ROLE_USER_ADMIN and ROLE_SUDO and add the previous user to it.
3. Log in with the new user and start a "Fast" workflow

Actual Results:
The workflow hangs in the Cleanup operation. Actually, the operation has failed but is not displayed in the admin UI.

Expected Results:
The workflow should run without problems

Workaround (if any):
Add the value "security/*" to the parameter "preserve-flavors" of the "cleanup" operation.