Revert UserManagerInterface::updateUser() BC break

[guilliamxavier]

Reverts #2896
Fixes #2896 (comment)

[guilliamxavier]

Travis failures unrelated (see #2961)

[XWB]

I believe the signature was incomplete, i.e. it is not compatible with https://github.com/FriendsOfSymfony/FOSUserBundle/blob/master/Doctrine/UserManager.php#L95

[guilliamxavier]

@XWB: Thanks for responding. But it is perfectly valid to have implementations with additional parameters as long as they are optional, for example:

interface UserInterface {}
class User implements UserInterface {}

interface UserManagerInterface {
    public function updateUser(UserInterface $user);
}
class SimpleUserManager implements UserManagerInterface {
    public function updateUser(UserInterface $user) { /* ... */ }
}
class DoctrineUserManager implements UserManagerInterface {
    public function updateUser(UserInterface $user, $andFlush = true) { /* ... */ }
}
class OtherUserManager implements UserManagerInterface {
    public function updateUser(UserInterface $user, array $extra = []) { /* ... */ }
}

https://3v4l.org/OKG5d

By adding , $andFlush = true to UserManagerInterface::updateUser signature to match DoctrineUserManager implementation, you break SimpleUserManager and OtherUserManager implementations

https://3v4l.org/SA1Ld
https://3v4l.org/VriK0