Add a link to a reported comment in the admin panel

Fix "There is no link to the reported comment in the admin interface" from https://github.com/diaspora/diaspora/issues/4711
Yeah I was thinking about writing it for both. I try to discover the syntax :P I guess the creation is something like that:
```
  before do
    @post = FactoryGirl.create(:post)
    @comment = FactoryGirl.create(:comment)
    post.comment = comment
  end
```