loxi-prep: remove uses of cstruct module
This module does not exist in PyLoxi.
diff --git a/tests/detailed_contr_sw_messages.py b/tests/detailed_contr_sw_messages.py
index 4ca6a6b..e4ebcfb 100644
--- a/tests/detailed_contr_sw_messages.py
+++ b/tests/detailed_contr_sw_messages.py
@@ -11,7 +11,7 @@
from oftest import config
import oftest.controller as controller
-import oftest.cstruct as ofp
+import ofp
import oftest.message as message
import oftest.dataplane as dataplane
import oftest.action as action