graphics_dEQP: fix corner case.

Don't access test_case before it is defined.

BUG=None.
TEST=Ran locally.

Change-Id: I7d16c71a2fed59917295f137219d992aecbe7b5b
Reviewed-on: https://chromium-review.googlesource.com/1539929
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Ilja H. Friedel <ihf@chromium.org>
Reviewed-by: Po-Hsien Wang <pwang@chromium.org>
diff --git a/client/site_tests/graphics_dEQP/graphics_dEQP.py b/client/site_tests/graphics_dEQP/graphics_dEQP.py
index 8f04e72..d23f93e 100644
--- a/client/site_tests/graphics_dEQP/graphics_dEQP.py
+++ b/client/site_tests/graphics_dEQP/graphics_dEQP.py
@@ -112,7 +112,7 @@
             test_results = {}
 
         if not os.path.isfile(result_filename):
-            failing_test.append(test_case)
+            logging.error('Did not find file %s', result_filename)
             return test_results
 
         with open(result_filename) as result_file: