Undo part of patch by Willys

A regression in tests was introduced by commit
1216309, intended to
fix issue #49.

Willys' code actually seems to make sense, but I chose
to undo it because
 - It appears to be extraneous to the issue #49
 - It does not fix the tests or remove the now-unused constant

Someone should re-fix it properly. But for now I prefer tests
continue to pass.

swift3/middleware.py

@@ -586,10 +586,11 @@ def PUT(self, env, start_response):
         self._app_call(env)
         status = self._get_status_int()
 
-        if status != HTTP_CREATED and status != HTTP_NO_CONTENT and \
-           status != HTTP_ACCEPTED:
+        if status != HTTP_CREATED and status != HTTP_NO_CONTENT:
             if status in (HTTP_UNAUTHORIZED, HTTP_FORBIDDEN):
                 return get_err_response('AccessDenied')
+            elif status == HTTP_ACCEPTED:
+                return get_err_response('BucketAlreadyExists')
             else:
                 return get_err_response('InvalidURI')