Merge branch 'split-with-2' into 'master'

Make sure we get only two returns

@DouweM The other change I made which has nothing to do with Gitlab::Email::Receiver

See merge request !3360

app/models/project.rb

@@ -304,7 +304,7 @@ class Project < ActiveRecord::Base
     end
 
     def find_with_namespace(id)
-      namespace_path, project_path = id.split('/')
+      namespace_path, project_path = id.split('/', 2)
 
       return nil if !namespace_path || !project_path