spec: remove nsswitch.conf scriptlet
    
    Related to: https://fedoraproject.org/wiki/Changes/Make_Authselect_Mandatory
    
    Both systemd and resolved nss modules are now enabled by default in
    authselect. Users are now expected to use authselect to configure
    the system and packages should no longer support non-authselect
    configurations.
    
    Resolves: rhbz#2023743