Finish up flake8 conversion.

Change-Id: I5034f19d5f9b20ad2b4569455273c730b1efec08
diff --git a/stress/test_server_actions.py b/stress/test_server_actions.py
index f4ddf23..3a7094d 100644
--- a/stress/test_server_actions.py
+++ b/stress/test_server_actions.py
@@ -19,10 +19,10 @@
 
 import random
 
-import pending_action
+from stress import pending_action
+from stress import test_case
 import stress.utils
 from tempest.exceptions import Duplicate
-import test_case
 
 
 class TestRebootVM(test_case.StressTestCase):