Add loadPasswords() calls to User password mutators

In User::setPassword() and User::setNewpassword(), added
calls to loadPasswords() so that the passwords are not
overridden when they are eventually actually loaded.

Bug: 69102
Change-Id: I0b881986323051abed7d1af816eae9eafdbd6782
(cherry picked from commit a223f2541b6874c82c204b5f07d26fe8d6bea31d)