Allow passing arbitrary connection objects

The fixed 'gerrit' and 'smtp' connection entries are deprecated.
We should allow users to pass in any connection information and
write that to the config file.

Change-Id: I4ebb7cd6b64d1854cd2e8e6e146572330558864c

manifests/init.pp

@@ -63,6 +63,7 @@ class zuul (
   $worker_username = '',
   $sites = [],
   $nodes = [],
+  $connections = [],
 ) {
   include ::httpd
   include ::pip

templates/zuul.conf.erb

@@ -6,6 +6,7 @@ check_job_registration=<%= @gearman_check_job_registration %>
 start=<%= @internal_gearman %>
 log_config=/etc/zuul/gearman-logging.conf
 
+<% if @gerrit_server != "" -%>
 [gerrit]
 server=<%= @gerrit_server %>
 user=<%= @gerrit_user %>
@@ -13,6 +14,7 @@ sshkey=/var/lib/zuul/ssh/id_rsa
 <% if @gerrit_baseurl != "" -%>
 baseurl=<%= @gerrit_baseurl %>
 <% end -%>
+<% end -%>
 
 [zuul]
 layout_config=/etc/zuul/layout/<%= @layout_file_name %>
@@ -75,6 +77,14 @@ accept_nodes=<%= @accept_nodes %>
 <% end -%>
 <% end -%>
 
+<% @connections.each do |connection| -%>
+[connection "<%= connection['name'] %>"]
+<% connection.each do |key,value| -%>
+<%= key %>=<%= value %>
+<% end -%>
+
+<% end -%>
+
 <% @sites.each do |site| -%>
 [site "<%= site['name'] %>"]
 host=<%= site['host'] %>