Merge commit 'refs/pull/1389/head' of https://github.com/magento/magento2 into MAGETWO-39123-new

Conflicts:
	app/code/Magento/Customer/Model/Customer/Attribute/Backend/Password.php

Author: okarpenko

app/code/Magento/Customer/Model/Customer/Attribute/Backend/Password.php

@@ -53,17 +53,8 @@ public function beforeSave($object)
                 );
             }
 
-            if ($this->string->substr(
-                $password,
-                0,
-                1
-            ) == ' ' || $this->string->substr(
-                $password,
-                $length - 1,
-                1
-            ) == ' '
-            ) {
-                throw new LocalizedException(__('The password can\'t begin or end with a space.'));
+            if (trim($password) != $password) {
+                throw new LocalizedException(__('The password can not begin or end with a space.'));
             }
 
             $object->setPasswordHash($object->hashPassword($password));