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.xsl

@@ -16,7 +16,6 @@
 
   <xsl:param name="fontDirectories" />
   <xsl:param name="fontconfig" />
-  <xsl:param name="fontconfigConfigVersion" />
 
   <xsl:template match="/fontconfig">
 
@@ -28,8 +27,8 @@
       <!-- /var/cache/fontconfig is useful for non-nixos systems -->
       <cachedir>/var/cache/fontconfig</cachedir>
 
-      <!-- versioned system-wide config -->
-      <include ignore_missing="yes">/etc/fonts/<xsl:value-of select="$fontconfigConfigVersion" />/conf.d</include>
+      <!-- system-wide config -->
+      <include ignore_missing="yes">/etc/fonts/conf.d</include>
 
       <dir prefix="xdg">fonts</dir>
       <xsl:for-each select="str:tokenize($fontDirectories)">