fix golint warn

pkg/spec/postgresql.go

@@ -135,13 +135,13 @@ func (m *MaintenanceWindow) MarshalJSON() ([]byte, error) {
 		return []byte(fmt.Sprintf("\"%s-%s\"",
 			m.StartTime.Format("15:04"),
 			m.EndTime.Format("15:04"))), nil
-	} else {
+	}
+
 	return []byte(fmt.Sprintf("\"%s:%s-%s\"",
 		m.Weekday.String()[:3],
 		m.StartTime.Format("15:04"),
 		m.EndTime.Format("15:04"))), nil
 }
-}
 
 // UnmarshalJSON convets a JSON to the maintenance window definition.
 func (m *MaintenanceWindow) UnmarshalJSON(data []byte) error {