Merge pull request #1428 from NickPresta/patch-1

website: Updating Ubuntu 12.04 ISO location and checksum

website/source/docs/builders/virtualbox-iso.html.markdown

@@ -26,8 +26,8 @@ Ubuntu to self-install. Still, the example serves to show the basic configuratio
 {
   "type": "virtualbox-iso",
   "guest_os_type": "Ubuntu_64",
-  "iso_url": "http://releases.ubuntu.com/12.04/ubuntu-12.04.3-server-amd64.iso",
-  "iso_checksum": "2cbe868812a871242cdcdd8f2fd6feb9",
+  "iso_url": "http://releases.ubuntu.com/12.04/ubuntu-12.04.5-server-amd64.iso",
+  "iso_checksum": "769474248a3897f4865817446f9a4a53",
   "iso_checksum_type": "md5",
   "ssh_username": "packer",
   "ssh_password": "packer",