Update cross-id tool link in help/cooking/general/crossid.aspx

[raddick]

Issue title: link broken?

From: Bob Zavala

Category: Question

Severity: Mild

Description:
Could not execute the query I expected to be able to perform.

Steps to reproduce:

1. From the web page
   http://skyserver.sdss.org/dr12/en/help/cooking/general/crossid.aspx
2. I clicked on Imaging Cross-Identification which said the link would open a new window.
3. This page opened
   http://skyserver.sdss.org/dr12/en/tools/crossid/upload.aspx
   and it displayed:
   An error has occurred in Skyserver
   The file '/dr12/en/tools/crossid/upload.aspx' does not exist.