nilfs2: update project's web site in nilfs2.txt

Project's web site was moved to nilfs.sourceforge.net from
www.nilfs.org.  This updates the site information in
Documentation/filesystems/nilfs2.txt with the new location.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/filesystems/nilfs2.txt

@@ -25,9 +25,8 @@ available from the following download page.  At least "mkfs.nilfs2",
 cleaner or garbage collector) are required.  Details on the tools are
 described in the man pages included in the package.
 
-Project web page:    http://www.nilfs.org/en/
-Download page:       http://www.nilfs.org/en/download.html
-Git tree web page:   http://www.nilfs.org/git/
+Project web page:    http://nilfs.sourceforge.net/
+Download page:       http://nilfs.sourceforge.net/en/download.html
 List info:           http://vger.kernel.org/vger-lists.html#linux-nilfs
 
 Caveats