UI: Error message is not proper when pool creation fails due to duplicate name
Steps to reproduce:
1. Go to pool list view
2. Create a new pool with name 'test1'
3. Try to create a another pool immediately with the same name 'test1'. This should be done before the pool which is created in the above step is listed in the ui.
4. "Unexpected Error 409" "
[object Object]" is shown
The error should be "Pool with name test2 already exists"