Use proper server name in repoman configuration

Repoman is not accessible from localhost in all configurations,
thus we instead use the proper servername configured in the wizard
to communicate with repoman for SVN repositories.

Related to https://github.com/finnlabs/addon-repositories/pull/5

packaging/conf/configuration.yml

@@ -49,7 +49,7 @@ default:
   <% if ENV['SVN_REPOSITORIES'].present? %>
     subversion:
       # SVN uses Apache repository wrapper due to permission errors in multi-user operation
-      manages: http://localhost/repoman_svn
+      manages: <%= ENV['SERVER_PROTOCOL'] %>://<%= ENV['SERVER_HOSTNAME'] %>/repoman_svn
       access_token: <%= ENV['SVN_REPOMAN_TOKEN'] %>
   <% end %>
 <% end %>