autoupdate: Get the unit test to pass again.

A few months ago the arguments to _GetArtifact were changed slightly but the
unittest for autoupdate.py wasn't updated. This gets it to pass again on ToT.

BUG=None
TEST=Ran the unittest and saw that it passes again.

Change-Id: Id624a34cf4f1322ad212ba6a8f9314bad38463ae
Reviewed-on: https://chromium-review.googlesource.com/216574
Reviewed-by: Simran Basi <sbasi@chromium.org>
Commit-Queue: Gabe Black <gabeblack@chromium.org>
Tested-by: Gabe Black <gabeblack@chromium.org>
diff --git a/autoupdate_unittest.py b/autoupdate_unittest.py
index 13c1f2c..402afc4 100755
--- a/autoupdate_unittest.py
+++ b/autoupdate_unittest.py
@@ -127,9 +127,8 @@
     au_mock = self._DummyAutoupdateConstructor()
 
     common_util.IsInsideChroot().AndReturn(True)
-    self._xbuddy._GetArtifact(
-        [''], board=self.test_board, lookup_only=True).AndReturn(
-            (latest_label, constants.TEST_IMAGE_FILE))
+    self._xbuddy._GetArtifact([''], board=self.test_board, lookup_only=True,
+        image_dir=None).AndReturn((latest_label, constants.TEST_IMAGE_FILE))
 
     au_mock.GenerateUpdateImageWithCache(
         os.path.join(self.static_image_dir, self.test_board, self.latest_dir,
@@ -204,8 +203,8 @@
     au_mock = self._DummyAutoupdateConstructor()
     au_mock.forced_image = "xbuddy:b/v/a"
 
-    self._xbuddy._GetArtifact(
-        ['b', 'v', 'a']).AndReturn(('label', constants.TEST_IMAGE_FILE))
+    self._xbuddy._GetArtifact(['b', 'v', 'a'],
+        image_dir=None).AndReturn(('label', constants.TEST_IMAGE_FILE))
 
     au_mock.GetUpdateForLabel(
         autoupdate.FORCED_UPDATE, 'b/v/a').AndReturn('p')