Config: Move OrderManager upgrade to Version management

config/versions/v4.go

@@ -0,0 +1,23 @@
+package versions
+
+import (
+	"context"
+)
+
+// Version4 implements ConfigVersion
+type Version4 struct {
+}
+
+func init() {
+	Manager.registerVersion(4, &Version4{})
+}
+
+// UpgradeConfig sets OrderManager config to defaults
+func (v *Version4) UpgradeConfig(_ context.Context, c []byte) ([]byte, error) {
+	return e, err
+}
+
+// DowngradeConfig doesn't need to do anything for this version
+func (v *Version4) DowngradeConfig(_ context.Context, e []byte) ([]byte, error) {
+	return e, nil
+}