MAGETWO-40274: Merge Branches and Stabilize Builds

 - updated AuthObserver for changes in Encryptor

Author: Cari Spruiell

app/code/Magento/User/Model/Backend/Observer/AuthObserver.php

@@ -130,10 +130,9 @@ public function adminAuthenticate($observer)
         $this->_checkExpiredPassword($latestPassword);
 
         // upgrade admin password
-        $isValidHash = $this->encryptor->isValidHashByVersion(
+        $isValidHash = $this->encryptor->isValidHash(
             $password,
-            $user->getPassword(),
-            Encryptor::HASH_VERSION_LATEST
+            $user->getPassword()
         );
         if (!$isValidHash) {
             $this->userFactory->create()