systemd.255-1.5: Only run daemon-reexec once during posttrans
    
    During systemd 255 -> 256 upgrade, we noticed systemd daemon-reexec
    being run 5 times in a row during upgrade:
    1. systemd 255 postun
    2. systemd udev 255 postun
    3. systemd container 255 postun
    4. systemd 255 triggerun
    5. systemd 256 posttrans
    
    All but 5 is unnecessary. To do this, we create a maintenance release
    for 255 with systemctl daemon-reexec only once during post transaction.
    This is always run at the end of the transaction so all uninstall/install
    scripts have already been run.