[api] render "obs_url" as well via /configuration

src/api/app/models/configuration.rb

@@ -17,6 +17,7 @@ class Configuration < ActiveRecord::Base
                    :allow_user_to_create_home_project => CONFIG['allow_user_to_create_home_project'],
                    :disallow_group_creation => CONFIG['disallow_group_creation_with_api'],
                    :change_password => CONFIG['change_passwd'],
+                   :obs_url => nil, # inital setup may happen in webui api controller
                    :hide_private_options => CONFIG['hide_private_options'],
                    :gravatar => CONFIG['use_gravatar'],
                    :download_url => CONFIG['download_url'],

src/api/config/options.yml.example

@@ -7,10 +7,6 @@
 # Make use of mod_xforward module in apache
 #use_xforward: true
 
-# Make use of http://blog.lighttpd.net/articles/2006/07/22/x-sendfiles-new-friend-x-rewrite.
-# Note that you need to enable the proxy-core option to allow this.
-#x_rewrite_host: localhost
-
 # Make use of X-Accel-Redirect for Nginx.
 # http://kovyrin.net/2010/07/24/nginx-fu-x-accel-redirect-remote
 #use_nginx_redirect: /internal_redirect 

src/backend/BSXML.pm

@@ -1488,6 +1488,7 @@ our $configuration = [
 	'enforce_project_keys',
 	'download_on_demand',
 	'download_url',
+	'obs_url',
 	'ymp_url',
 	'errbit_url',
 	'bugzilla_url',