Remove unneccessary sleep

The test still passes even with long sleeps inside the threads before
`server.start`. I'm guessing the servers bind to the port on
initialization and then start handling requests once started.

test/links_on_a_page_test.rb

@@ -19,7 +19,6 @@ def test_it_does_something_useful
     Thread.new do
       @server.start
     end
-    sleep 1
 
     quarantine_entrance = "http://localhost:#{@server.config[:Port]}"
     config = DocDoc::Configuration::Options.new(quarantine_entrance, nil)