Ensure database is only closed if it is open in closeDb function

web/server/db.js

@@ -475,7 +475,9 @@ export function flushPendingSave() {
  */
 export function closeDb() {
   flushPendingSave();
-  db.close();
+  if (db.open) {
+    db.close();
+  }
 }
 
 export default db;