Revert "Update horizon manifest to use new ssl variable names"

Because the dependent patch[1] does not present in stable/victoria
we should not merge this patch until stable/victoria release is created
for TripleO projects.
This revert will be reverted once stable/victoria branch is created.

[1] https://review.opendev.org/#/c/758041/

This reverts commit 09d7aa8834.

Closes-Bug: #1901626
Change-Id: Ica99237cbb92cf9d23e067490c2dce5fd5101457

manifests/profile/base/horizon.pp

@@ -104,8 +104,8 @@ class tripleo::profile::base::horizon (
     class { 'horizon':
       cache_server_ip => $horizon_memcached_servers,
       neutron_options => $neutron_options_real,
-      ssl_cert        => $tls_certfile,
-      ssl_key         => $tls_keyfile,
+      horizon_cert    => $tls_certfile,
+      horizon_key     => $tls_keyfile,
     }
   }
 }