On EL7, Require: systemd instead of systemd-udev (#2157788)
    
    It appears that the udev directories
    
        /etc/udev/rules.d/
        /usr/lib/udev/rules.d/
    
    were split off from the systemd package into the systemd-udev package
    some time after EL7, so a beep package for EL7 and earlier can only
    "Require:" systemd, not the systemd-udev package introduced later.
    
    Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2157788