Fix samples extensions. Add icons (nothing building or testable)

chrome/test/data/extensions/samples/subscribe_page_action/manifest.json

 {
   "name": "RSS Subscription Extension",
   "description": "Adds one-click subscription to your toolbar",
-  "version": "1.2.5",
+  "version": "1.3",
   "permissions": [
     "tabs",
     "http://*/*"
   ],
   "background_page": "background.html",
   "content_scripts": [
     {
       "matches": ["http://*/*", "file://*.*"],
       "js": ["feed_finder.js"]
     }
   ],
+  "icons": { "128": "feed-icon-128x128.png" },
   "page_actions": [
     {
       "id": "RssPageAction",
       "name": "Subscribe to this feed",
       "icons": [
          "feed-icon-16x16.png"
       ]
     }
   ]
 }