The initSession method has not been changed

Reproduce the error: When changing the password of the user from "User settings", it throws an fatal error.

Why ? : The initSession method has not been changed in the processPasswordChange method of the UsersManager Controller class.
Missing SessionInitializer namespace
Merge pull request #6455 from burakcakirel/master

Use SessionInitializer in UsersManager.processPasswordChange since initSession method has moved from Auth to aforementioned class.