fontconfig: get rid of rest of versioned configs

The incompatibility does not seem to exist any more: programs linked against fc 2.12
on fc 2.14 system seem to at least display text, even while printing tons of errors
(as long as you generate fc cache manually), and same thing the other way around.
Hopefully it will not be an issue in the future.

pkgs/development/libraries/fontconfig/make-fonts-conf.nix

@@ -10,7 +10,6 @@ runCommand "fonts.conf"
   ''
     xsltproc --stringparam fontDirectories "$fontDirectories" \
       --stringparam fontconfig "${fontconfig.out}" \
-      --stringparam fontconfigConfigVersion "${fontconfig.configVersion}" \
       --path ${fontconfig.out}/share/xml/fontconfig \
       ${./make-fonts-conf.xsl} ${fontconfig.out}/etc/fonts/fonts.conf \
       > $out