SECURITY: Add CSRF token on Special:ChangePassword

Use a login token when logged out user is using Special:ChangePassword
(should only happen when a user is forced to reset their password to
complete the login process).

Logged in users are not logged in as an effect of resetting their
password, and for them, the edit token check should be sufficient.

Bug: 62497
Change-Id: I08afed3e1aeeb8c97d24fe9858a3ba2c03e92adf