Revert "Shorter Sinatra::Runner timeout" (#1976)

This reverts commit 0e43702.

This wasn't needed for anything more than making the tests fail faster
when I was developing. It could be seen as a breaking change, so let's
just back it out.

sinatra-contrib/lib/sinatra/runner.rb

@@ -111,7 +111,7 @@ def command
       "bundle exec ruby #{app_file} -p #{port} -e production"
     end
 
-    def ping(timeout = 10)
+    def ping(timeout = 30)
       loop do
         return if alive?