[File Manager] Removing a debug change

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10134050

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@133882 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/resources/file_manager/js/file_manager.js

@@ -2487,7 +2487,7 @@ FileManager.prototype = {
   };
 
   FileManager.prototype.isOffline = function() {
-    return !!navigator.onLine;
+    return !navigator.onLine;
   };
 
   FileManager.prototype.onOnlineOffline_ = function() {