refactor: openpitrix module

Signed-off-by: hongming <talonwan@yunify.com>

vendor/github.com/koding/multiconfig/multiloader.go

@@ -0,0 +1,27 @@
+package multiconfig
+
+type multiLoader []Loader
+
+// MultiLoader creates a loader that executes the loaders one by one in order
+// and returns on the first error.
+func MultiLoader(loader ...Loader) Loader {
+	return multiLoader(loader)
+}
+
+// Load loads the source into the config defined by struct s
+func (m multiLoader) Load(s interface{}) error {
+	for _, loader := range m {
+		if err := loader.Load(s); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+// MustLoad loads the source into the struct, it panics if gets any error
+func (m multiLoader) MustLoad(s interface{}) {
+	if err := m.Load(s); err != nil {
+		panic(err)
+	}
+}