There are base test classes namely `SyncTestCase` and
`AsyncTestCase` which we would like all test classes in
this code base to extend.
This commit extends the listed classes in test_storage.py
to extend the above mentioned base classes:
* UtilTests
* BucketProxy
* Server
Signed-off-by: Fon E. Noel NFEBE <fenn25.fn@gmail.com>
