ipatests: Fix usage of token_password_file
    
    There were a few hardcoded places where it was set to
    /tmp/token_passwd instead of using the class variable.
    
    Don't rely on previous running tests installing the token
    password file so they can be run individually.
    
    Fixes: https://pagure.io/freeipa/issue/9603
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>