Bug 572970 - Hardcode some pre-processed values for .in files like prefs and constants [r=mconnor]

* Rename prefs.js.in to prefs.js
* Hardcode server_url

services/sync/services-sync.js

@@ -1,4 +1,4 @@
-pref("services.sync.serverURL", "@server_url@");
+pref("services.sync.serverURL", "https://auth.services.mozilla.com/");
 pref("services.sync.storageAPI", "1.0");
 pref("services.sync.userURL", "user/");
 pref("services.sync.miscURL", "misc/");