Merge "Clarify horizon allowed hosts setting"

diff --cc puppet/services/horizon.yaml
index 6ea5ec4,bdb171a..1e08415
--- 1/puppet/services/horizon.yaml
--- 2/puppet/services/horizon.yaml
+++ b/puppet/services/horizon.yaml
@@@ -24,13 -20,9 +24,14 @@@ parameters
      type: json
    HorizonAllowedHosts:
      default: '*'
-     description: A list of IP/Hostname allowed to connect to horizon
+     description: A list of IP/Hostname for the server Horizonis running on.
+                  Used for header checks.
      type: comma_delimited_list
 +  HorizonSecret:
 +    description: Secret key for Django
 +    type: string
 +    hidden: true
 +    default: ''
    NeutronMechanismDrivers:
      default: 'openvswitch'
      description: |