Remove Nova v3 API test configuration

Nova v3 API has disappeared in Juno cycle, and we don't test the API
now on the gate since If63dcdb2d05aa0fab0b6848a1248b6678f1ee9ad .
This patch removes Nova v3 API test configuration.

Change-Id: Ie2e10d603e10b0f05ec7767ea41b5fe9aca84ccc
Merge "Remove Nova v3 API test configuration"