Fixes selinux Horizon Bug

Commit ID: ebeda3c6ee introduced
a boolean set for selinux.  The condition did not properly
evaluate the selinux system fact.  The condition now evaluates the
selinux fact and the selinux string.

Change-Id: Ic58726276ca2163823c58feb26fb07644af9685d

manifests/horizon.pp

@@ -101,7 +101,7 @@ class openstack::horizon (
     api_result_limit      => $api_result_limit,
   }
 
-  if $::selinux {
+  if $::selinux and $::selinux != 'false' {
     selboolean{'httpd_can_network_connect':
       value      => on,
       persistent => true,