Description of change
Check the role binding has been deleted before starting to create a new one;
QA steps
- deploy any caas charm has RBAC resources;
- upgrade charm to see if role binding could be created;
Documentation changes
None
Bug reference
https://bugs.launchpad.net/juju/+bug/1845696
该提问来源于开源项目：juju/juju
