Can not access git repository when "Subdirectory for HTTP access" is set

* app/controllers/git_http_controller.rb (GitHttpController#index): Strip
  "Subdirectory for HTTP access" prefix from repository path.
Merge pull request #24 from baby-gnu/hotfix/strip-http-prefix-from-repository-path

Can not access git repository when "Subdirectory for HTTP access" is set
Thank you!