HTK: support csv list in oslo conf rendering

Some configuration options that with older openstack releases
were multistrings have now changed to csv values under a single
key, this change makes that simple to accomodate.

Change-Id: Id941a1e56e4a852d764084c958c13588b8e3ed85
Signed-off-by: Pete Birley <pete@port.direct>

helm-toolkit/templates/utils/_to_oslo_conf.tpl

@@ -28,6 +28,12 @@ values: |
           values:
             - messagingv2
             - log
+      oslo_messaging_notifications_stein:
+        driver: # An example of a csv option's syntax
+          type: csv
+          values:
+            - messagingv2
+            - log
       security_compliance:
         password_expires_ignore_user_ids:
         # Values in a list will be converted to a comma separated key
@@ -41,6 +47,8 @@ return: |
   [oslo_messaging_notifications]
   driver = messagingv2
   driver = log
+  [oslo_messaging_notifications_stein]
+  driver = messagingv2,log
   [security_compliance]
   password_expires_ignore_user_ids = 123,456
 */}}
@@ -57,7 +65,9 @@ return: |
 {{- range $k, $multistringValue := $value.values -}}
 {{ $key }} = {{ $multistringValue }}
 {{ end -}}
-{{- end -}}
+{{ else if eq $value.type "csv" -}}
+{{ $key }} = {{ include "helm-toolkit.utils.joinListWithComma" $value.values }}
+{{ end -}}
 {{- else -}}
 {{ $key }} = {{ $value }}
 {{ end -}}