Simplify and modernize the specfile
    
    - Get rid of all conditions that are always true for both EPEL-7 and Fedora
      as it's quite unlikely we'd use this specfile on EPEL-6
    - Remove the sysvinit script and all the scriptlets around it
    - Unconditionally use systemd scriptlet macros and systemd_requires
    - Unconditionally build the PAM module as the PADL module is long dead
    - Remove the auto-migration of settings from nss_ldap as it's been
      long gone from Fedora
    - Don't check /etc/sysconfig/authconfig as authconfig is on its way
      out from Fedora
    - Use only spaces, not tabs, to stop my editor from looking like a
      Christmas tree
    - Remove the obsolete Group stanza
    - Make nscd Recommended, not Required