Update to 2.4.0
    
    - New upstream release 2.4.0
      - geoipupdate now checks that the database directory is writable: if it is
        not, it reports the problem and aborts
      - geoipupdate now acquires a lock when starting up to ensure only one
        instance may run at a time: a new option, 'LockFile', exists to set the
        file to use as a lock ('.geoipupdate.lock' in the database directory by
        default)
      - geoipupdate now prints out additional information from the server when a
        download request results in something other than HTTP status 2xx; this
        provides more information when the API does not respond with a database
        file
      - ${datarootdir}/GeoIP is now created on 'make install' (GH#29)
      - Previously, a variable named 'ERROR' was used, which caused issues building
        on Windows (GH#36)
    - Drop EL-5 support
      - Drop BuildRoot: and Group: tags
      - Drop explicit buildroot cleaning in %install section
      - Drop explicit %clean section
      - noarch subpackages always available now
      - libcurl-devel always available now