Revert "component/fontconfig: Bump fontconfig version (fix for FTBFS with glibc 2.25)."

This reverts commit 38123b86.

fontconfig was not building any more on many machines (most testnode machines). Revert
until investigation is done.

component/fontconfig/buildout.cfg

@@ -13,8 +13,8 @@ parts =
 
 [fontconfig]
 recipe = slapos.recipe.cmmi
-url = http://fontconfig.org/release/fontconfig-2.12.5.tar.bz2
-md5sum = e4d04a7723a66ae4db2a47703de00880
+url = http://fontconfig.org/release/fontconfig-2.12.1.tar.bz2
+md5sum = b5af5a423ee3b5cfc34846838963c058
 pkg_config_depends = ${freetype:pkg_config_depends}:${freetype:location}/lib/pkgconfig:${libxml2:location}/lib/pkgconfig
 # XXX-Cedric : should we use --with-add-fonts={somefont:location}/share,{someotherfont:location}/share?
 configure-options =