cros: Fix file open rescan directory callback on Linux

Fix a callback when we're running linux_chromeos

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/8565033

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109993 0039d316-1c4b-4281-b951-d872f2087c98

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

@@ -3069,7 +3069,8 @@ FileManager.prototype = {
     spliceArgs.unshift(0, 0);  // index, deleteCount
     this.dataModel_.splice.apply(this.dataModel_, spliceArgs);
 
-    rescanDone();
+    if (opt_callback)
+      opt_callback();
   };
 
   FileManager.prototype.findListItem_ = function(event) {