[s3acl] Step 0: Put bucket ACL only responds success if the ACL is private. (#4856)

* Passing test:
test_bucket_acl_default
test_bucket_acl_canned_private_to_private

https://github.com/seaweedfs/seaweedfs/issues/4519

* Update weed/s3api/s3api_bucket_handlers.go

---------

Co-authored-by: Konstantin Lebedev <9497591+kmlebedev@users.noreply.github.co>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>

docker/compose/s3tests.conf

@@ -18,10 +18,10 @@ bucket prefix = yournamehere-{random}-
 
 [s3 main]
 # main display_name set in vstart.sh
-display_name = M. Tester
+display_name = s3_tests
 
 # main user_idname set in vstart.sh
-user_id = testid
+user_id = s3_tests
 
 # main email set in vstart.sh
 email = tester@ceph.com