On the '1.3.x-r1901040' branch: A minor test output tweak.

* test/test_context.c
  (format_cert_failures): Use serf__log() to output debug information.


git-svn-id: https://svn.apache.org/repos/asf/serf/branches/1.3.x-r1901040@1909285 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/test/test_context.c b/test/test_context.c
index a179219..4e44bbe 100644
--- a/test/test_context.c
+++ b/test/test_context.c
@@ -1164,7 +1164,7 @@
     }
 
     if (failures) {
-        printf("Unexpected or unknown cert failure\n");
+        serf__log(TEST_VERBOSE, __FILE__, "Unexpected or unknown cert failure\n");
         abort();
     }