Autotest: fix for bug in touch_ScrollDirection test.

TEST=ran it
BUG=None

Change-Id: I18c4e0d4ef557946244c4bf433896217be2324ef
Reviewed-on: https://chromium-review.googlesource.com/218783
Reviewed-by: Kris Rambish <krisr@chromium.org>
Commit-Queue: Katherine Threlkeld <kathrelkeld@google.com>
Tested-by: Katherine Threlkeld <kathrelkeld@google.com>
diff --git a/client/site_tests/touch_ScrollDirection/touch_ScrollDirection.py b/client/site_tests/touch_ScrollDirection/touch_ScrollDirection.py
index 6705408..45d6a46 100644
--- a/client/site_tests/touch_ScrollDirection/touch_ScrollDirection.py
+++ b/client/site_tests/touch_ScrollDirection/touch_ScrollDirection.py
@@ -28,7 +28,7 @@
 
         """
         self._reset_scroll_position()
-        self._playback(filepath=self._down_file)
+        self._playback(filepath=filename)
         self._wait_for_scroll_position_to_settle()
 
         delta = self._get_scroll_position() - self._DEFAULT_SCROLL