Fix #5678 (#5681)

* Fix #5678

* Revert "Fix #5678"

This reverts commit 106b6ddd9535da6ec323226c1b9ad649022aeb1e.

* revert #5627

src/Adapters/Storage/Mongo/MongoStorageAdapter.js

@@ -126,8 +126,6 @@ export class MongoStorageAdapter implements StorageAdapter {
   client: MongoClient;
   _maxTimeMS: ?number;
   canSortOnJoinTables: boolean;
-  databaseVersion: string;
-  engine: string;
 
   constructor({
     uri = defaults.DefaultMongoURI,
@@ -138,7 +136,6 @@ export class MongoStorageAdapter implements StorageAdapter {
     this._collectionPrefix = collectionPrefix;
     this._mongoOptions = mongoOptions;
     this._mongoOptions.useNewUrlParser = true;
-    this.engine = 'MongoDB';
 
     // MaxTimeMS is not a global MongoDB client option, it is applied per operation.
     this._maxTimeMS = mongoOptions.maxTimeMS;
@@ -962,15 +959,7 @@ export class MongoStorageAdapter implements StorageAdapter {
   }
 
   performInitialization(): Promise<void> {
-    // databaseVersion
-    return this.connect()
-      .then(() => {
-        const adminDb = this.database.admin();
-        return adminDb.serverStatus();
-      })
-      .then(status => {
-        this.databaseVersion = status.version;
-      });
+    return Promise.resolve();
   }
 
   createIndex(className: string, index: any) {