Drop installation-time dependency on systemd
    
    For rdma-core binary package, the dependency is really on systemd-udev
    which provides udevadm. Since systemd can be installed without udev,
    the dependency was not effective. But actually the dependency is not
    needed at all, because the system will behave the same with and
    without it. (If systemd-udev is installed later in the transaction,
    the call to udevadm trigger is not necessary. If systemd-udev is
    installed earlier in the transaction, the call to udevadm trigger will
    succeed. And if if systemd-udev is not installed at all, it means that
    there's no hardware support and udevadm doesn't need to be executed at
    all.)
    
    Similarly, %{systemd_requires} is not necessary for the systemd unit
    scriptlets. See https://pagure.io/packaging-committee/c/46010f8b6ab077bf.
    That commit also has a long explanation.
    
    Also co-own the directory to avoid unowned directory warning.