Allow setting tls_priority option

Add tls_priority config option to libvirtd.conf config.

libvirt-4.0.0 supports this functionality out of the box.

To fully comply with PROD-27620 priority string should be set in reclass
to the following string:

  SECURE256:-VERS-ALL:+VERS-TLS1.2:-KX-ALL:+ECDHE-RSA:+ECDHE-ECDSA:\
  -CIPHER-ALL:+AES-256-GCM:+AES-256-CBC:-MAC-ALL:+AEAD:+SHA384

Also, fix some inconsistiences found:

* tests/pillar/compute_single.sls - change qemu's group name to 'nova' as
  'cinder' does not exists.

Change-Id: I56a8c3726e1af274e2d2fffce8dca4501745519e
Related-Prod: PROD-27620
(cherry picked from commit 77d9dacf644b1c8a93dcc35d30d90b046b86c9fa)
diff --git a/.kitchen.yml b/.kitchen.yml
index 6f06138..af3150d 100644
--- a/.kitchen.yml
+++ b/.kitchen.yml
@@ -71,5 +71,20 @@
             controller:
               version: <%= ENV['OS_VERSION'] || 'ocata' %>
 
+  - name: compute_single_ssl
+    driver:
+      devices:
+        - /dev/mem
+      cap_add:
+        - SYS_RAWIO
+    provisioner:
+      pillars-from-files:
+        compute_single.sls: tests/pillar/compute_single.sls
+        nova.sls: tests/pillar/compute_single_ssl.sls
+      pillars:
+        release.sls:
+          nova:
+            compute:
+              version: <%= ENV['OS_VERSION'] || 'ocata' %>
 
 # vim: ft=yaml sw=2 ts=2 sts=2 tw=125