Drop scriptlet for handling nobody user upgrades from Fedora <28
    
    For https://fedoraproject.org/wiki/Changes/RenameNobodyUser a scriptlet
    was introduced with prevents nss-systemd from synthesizing entries for nobody.
    Let's remove the scriptlet: very few people upgrade from such old systems,
    and even if they do, having a duplicate entry for nobody is annoying
    but hardly a big problem.
    
    (The other side of this, support in nss-systemd remains in place.)
    
    This allows deps on the tools used in the scriptlet to be dropped from -libs.
    
    While at it, also drop noop ldconfig scriptlets.