Finish up flake8 conversion.

Change-Id: I5034f19d5f9b20ad2b4569455273c730b1efec08
diff --git a/stress/test_servers.py b/stress/test_servers.py
index 25cbbb0..1dd72f1 100644
--- a/stress/test_servers.py
+++ b/stress/test_servers.py
@@ -19,8 +19,8 @@
 
 import random
 
-import pending_action
-import test_case
+from stress import pending_action
+from stress import test_case
 
 
 class TestCreateVM(test_case.StressTestCase):