Description
the user with the right to change the password (user/password) cannot change it

Steps to reproduce
1.  Install eZ Platform 3
2.  Add new User
3.  Set policies for a user, to login and user/password as in doc (https://doc.ezplatform.com/en/3.0/guide/user_management/#passwords)
4. Log in to the user and try to change the password

Actual
Cannot change password, get an error like: 
The User does not have the 'edit' 'content' permission with: contentId '56'

Except
Can change the password without any extra polices

In eZ Platform 2.5 polices work properly