Use the existing protocol when connecting to the flicker API

Testing the tutorial on https hangs -
"[blocked] The page at 'https://deliteful-tutorial-c9-funland.c9.io/index.html' was loaded over HTTPS, but ran insecure content from 'http://api.flickr.com/services/feeds/photos_public.gne?format=json&jsoncallback=photosReceived&tags=famous,bridges&tagmode=all': this content should also be loaded over HTTPS." 

Updated the flicker API request to reuse the existing protocol.