activeadmin/activeadmin — pull request #3365 by timoschilling (2014-08-26 13:38:24+00:00)
Title: fix site title of namespaces

Bug:
With this configuration:
```ruby
ActiveAdmin.setup do |config|
config.site_title = "Root"
config.namespace :sub do |sub|
sub.site_title = "Sub"
end
end
```
The site title (

tag), keeps "Root" for all namespaces.