Adds explicit status code 301 permanent redirect to catalog#update

The redirect called in the catalog#update method is defaulting to a 302 redirect: http://api.rubyonrails.org/classes/ActionController/Redirecting.html#method-i-redirect_to

Since Google is evaluating JS these days, that is destroying the SEO on the search results page. (i.e. my guess is Google bots ARE posting to the update method and being redirected with 302, instead of sent to the fallback GET) 

Added an explicit 301 redirect to pass the "link juice" for SEO optimization (src: http://moz.com/learn/seo/redirection).