staging/lustre: Replace sun.com GPLv2 URL with gnu.org one.

http://www.sun.com/software/products/lustre/docs/GPLv2.pdf is no
longer around, so replae it with (hopefully more permanent)
http://http://www.gnu.org/licenses/gpl-2.0.html

Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Reported-by: Xose Vazquez Perez <xose.vazquez@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/staging/lustre/lustre/mdc/mdc_request.c b/drivers/staging/lustre/lustre/mdc/mdc_request.c
index e152429..12cb238 100644
--- a/drivers/staging/lustre/lustre/mdc/mdc_request.c
+++ b/drivers/staging/lustre/lustre/mdc/mdc_request.c
@@ -15,7 +15,7 @@
  *
  * You should have received a copy of the GNU General Public License
  * version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ * http://www.gnu.org/licenses/gpl-2.0.html
  *
  * GPL HEADER END
  */