Bug 2-2-stable fix: issue with cart_link not displaying in https

(I guess due to mixed-mode ssl)

fixes issue with cart_link not displaying (I guess due to mixed-mode ssl)

This is due to https calls to /cart-link redirecting to http
I expect if I'm in https mode any calls should also be in https.

Using 2-2-stable and Rails 4.0.3

This occurs when there are products in the cart, and when in https mode within the Checkout process the following occurs:

I, [2014-03-30T14:03:31.852561 #1867]  INFO -- : Started GET "/cart_link" for 200.200.200.200 at 2014-03-30 14:03:31 +1100
I, [2014-03-30T14:03:31.858300 #1867]  INFO -- : Processing by Spree::StoreController#cart_link as */*
I, [2014-03-30T14:03:31.859980 #1867]  INFO -- : Redirected to http://url.com/cart_link
I, [2014-03-30T14:03:31.860096 #1867]  INFO -- : Filter chain halted as :force_non_ssl_redirect rendered or redirected
I, [2014-03-30T14:03:31.860236 #1867]  INFO -- : Completed 301 Moved Permanently in 2ms (ActiveRecord: 0.0ms)