Bug 1046297: change frequency of about:home snippets requests to once every 4 hours, r=mak

--HG--
extra : transplant_source : c%01%A2A%FC%C7%A1%3A%F7%12%E6z%B8%C7tK3%E2F%8B

browser/base/content/abouthome/aboutHome.js

@@ -146,7 +146,7 @@ const DEFAULT_SNIPPETS_URLS = [
 , "https://addons.mozilla.org/firefox/?utm_source=snippet&utm_medium=snippet&utm_campaign=addons"
 ];
 
-const SNIPPETS_UPDATE_INTERVAL_MS = 86400000; // 1 Day.
+const SNIPPETS_UPDATE_INTERVAL_MS = 14400000; // 4 hours.
 
 // IndexedDB storage constants.
 const DATABASE_NAME = "abouthome";