fixup! Bug 10760: Integrate TorButton to TorBrowser core

Bug 41519: honor the TOR_SOCKS_IPC_PATH variable

Add back FileUtils which was accidentaly removed in 004b629b
Fixes: "ReferenceError: FileUtils is not defined startup-observer.js:121"

toolkit/torbutton/components/startup-observer.js

@@ -26,6 +26,7 @@ const { TorProtocolService } = ChromeUtils.import(
 
 XPCOMUtils.defineLazyModuleGetters(this, {
   ComponentUtils: "resource://gre/modules/ComponentUtils.jsm",
+  FileUtils: "resource://gre/modules/FileUtils.jsm",
 });
 
 // Module specific constants