mesa3d: fix download URL

The MesaLib 7.10.3 tarball has been moved on ftp.freedesktop.org from
pub/mesa/7.10.3/ to pub/mesa/old_versions/7.x/7.10.3/.
A bump to a newer release is only coming after Buildroot 2013.08, so for now
let us just change URL to let the download work properly.

Reported-by: Ryan Wilkins <ryan@deadfrog.net>
Signed-off-by: Luca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>

package/x11r7/mesa3d/mesa3d.mk

@@ -6,7 +6,7 @@
 
 MESA3D_VERSION = 7.10.3
 MESA3D_SOURCE = MesaLib-$(MESA3D_VERSION).tar.gz
-MESA3D_SITE = ftp://ftp.freedesktop.org/pub/mesa/$(MESA3D_VERSION)
+MESA3D_SITE = ftp://ftp.freedesktop.org/pub/mesa/older-versions/7.x/$(MESA3D_VERSION)
 MESA3D_LICENSE = MIT, SGI, Khronos
 MESA3D_LICENSE_FILES = docs/license.html