private void groupUserDeleted(Group group, JID deletedUser) {
        groupUserDeleted(group, getAffectedUsers(group), deletedUser);
    }
Notification that a Group user has been deleted. Update the group users' roster accordingly.

@param group the group from where the user was deleted.
@param deletedUser the username of the user that has been deleted from the group.
xmppserver/src/main/java/org/jivesoftware/openfire/roster/RosterManager.java