Prevent Google indexing of the SiteNotice div

Site notice and CentralNotice should be omitted from search snippets.
We're diluting page content.

The awkward thing about this patch is that we can only confirm the
googleoff tag is supported for the search appliance, not the public
web crawler.  See here for those docs, though:
http://static.googleusercontent.com/media/www.google.com/en/us/support/enterprise/static/gsa/docs/admin/70/gsa_doc_set/admin_crawl/admin_crawl.pdf

Change-Id: I95473e22de83e585044a4f917bbd1b00db7db71b
Merge "Prevent Google indexing of the SiteNotice div"