fix schem url for system dayabase

Author: Francesca-Bit

lib/connectionConfig.js

@@ -479,6 +479,7 @@ ConnectionConfig.prototype.queryURL = function () {
  * @returns {string}
  */
 ConnectionConfig.prototype.log = function () {
+  if (this.db() === this.system_db) return this.dbBase('log');
   return this.branchBase('log');
 };
 
@@ -735,6 +736,9 @@ ConnectionConfig.prototype.queryParameter = function (params) {
 
 ConnectionConfig.prototype.jsonSchemaURL = function (params) {
   const paramsStr = this.queryParameter(params);
+  if (this.db() === this.system_db) {
+    return this.dbBase('schema') + paramsStr;
+  }
   return this.branchBase('schema') + paramsStr;
 };