Use raw strings for Python 3 compatibility in old API client code
    
    Python 3 enforces checks on \ sequences in strings. Instead of copying
    over the new mix of normal and raw strings from the server side, turn
    those strings in the remote plugins to raw mode.
    
    Fixes: https://pagure.io/freeipa/issue/9565
    
    Signed-off-by: Alexander Bokovoy <abokovoy@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>