PAM changes for supporting duo 2FA solution

Multi-Factor Authentication (MFA) for sshd+PAM
https://duo.com/product/multi-factor-authentication-mfa

Related-Prod: PROD-24422
Change-Id: Iddec5a5e99e7db5d7f173ad939d3fd0cac1cd22b
diff --git a/.kitchen.yml b/.kitchen.yml
index 122f5de..dce7fe2 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -71,4 +71,9 @@
         - source: tests/example
           dest: srv/salt/linux/files/test
 
+  - name: duo
+    provisioner:
+      pillars-from-files:
+        linux.sls: tests/pillar/system_duo.sls
+
 # vim: ft=yaml sw=2 ts=2 sts=2 tw=125