Bug 758101 - Re-enable background updates on mozilla-central; r=rstrong

--HG--
extra : rebase_source : 30c936bd2d5a52c4a4070becf425394d75db92ec

browser/app/profile/firefox.js

@@ -147,7 +147,7 @@ pref("app.update.silent", false);
 
 // If set to true, the Update Service will apply updates in the background
 // when it finishes downloading them.
-pref("app.update.stage.enabled", false);
+pref("app.update.stage.enabled", true);
 
 // Update service URL:
 pref("app.update.url", "https://aus3.mozilla.org/update/3/%PRODUCT%/%VERSION%/%BUILD_ID%/%BUILD_TARGET%/%LOCALE%/%CHANNEL%/%OS_VERSION%/%DISTRIBUTION%/%DISTRIBUTION_VERSION%/update.xml");