port stub_object_storage changes

spec/support/helpers/stub_object_storage.rb

@@ -15,9 +15,14 @@ module StubObjectStorage
 
     return unless enabled
 
+    stub_object_storage(connection_params: uploader.object_store_credentials,
+                        remote_directory: remote_directory)
+  end
+
+  def stub_object_storage(connection_params:, remote_directory:)
     Fog.mock!
 
-    ::Fog::Storage.new(uploader.object_store_credentials).tap do |connection|
+    ::Fog::Storage.new(connection_params).tap do |connection|
       begin
         connection.directories.create(key: remote_directory)
       rescue Excon::Error::Conflict