Revert "test_bucket_create_exists should fail on recreate"

This reverts commit c82649b6353893770af8cd453af38d61dfd1e363.

The suite does not support duality in behaviors (e.g.
US Standard vs. Regional behavior) so we adhere to US
Standard only.

Signed-off-by: Alfredo Deza <alfredo@deza.pe>