Removes `defined?` in favor to just `if`

app/views/layouts/header/_default.html.haml

@@ -37,6 +37,6 @@
       %h1.title= title
 
 = render 'shared/outdated_browser'
--if defined?(@project)
+-if @project
   :javascript
     var findFileURL = '#{namespace_project_find_file_path(@project.namespace, @project, @ref || @project.repository.root_ref)}';
\ No newline at end of file