Fix the firewall rules for PostgreSQL

I got the source and destination mixed up.

site-cookbooks/kosmos-postgresql/recipes/default.rb

@@ -62,11 +62,11 @@ postgresql_replicas.each do |replica|
   unless node.chef_environment == "development"
     include_recipe "firewall"
 
-    firewall_rule "postgresql" do
+    firewall_rule "postgresql replica #{replica[:hostname]}" do
       port        5432
       protocol    :tcp
       command     :allow
-      destination replica[:ipaddress]
+      source replica[:ipaddress]
     end
   end
 end