s3api: fix devauth auth failure handling

swift/auth/server.py

@@ -442,6 +442,7 @@ YOU HAVE A FEW OPTIONS:
         headers = {}
         if 'Authorization' in request.headers:
             validation = self.validate_s3_sign(request, token)
+            if validation:
                 headers['X-Auth-Account-Suffix'] = validation[3]
         else:
             validation = self.validate_token(token)