azure: Collect systemd boot log
    
    If an error occured while containers setup phase then no logs will
    be collected and it is hard(impossible?) to debug such issues on
    remote Azure host. With this change in case of such error all the
    container's journals will be collected in `systemd_boot_logs`.
    
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>