Use the compound statement formatting API for configuring PKINIT
    
    Use `if_branch` and `else_branch` context managers instead of raw
    `command` calls in the method that generates Bash snippet that
    configures PKINIT on the master.
    
    https://pagure.io/freeipa/issue/7036
    
    Reviewed-By: Florence Blanc-Renaud <frenaud@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>