Add bandit python security scanning to pep8

This change adds bandit python security code scanning to the
pep8 zuul check.

Change-Id: I8b6c52bd3fae87c5b49f3cde8bb9e63526155973
diff --git a/test-requirements.txt b/test-requirements.txt
index 9085c07..a08c27a 100644
--- a/test-requirements.txt
+++ b/test-requirements.txt
@@ -8,3 +8,4 @@
 nose>=1.3.7 # LGPL
 nosexcover>=1.0.10 # BSD
 oslotest>=3.2.0 # Apache-2.0
+bandit>=1.5 # Apache-2.0