simple check for http dont check valid server string

The simple check for http only check if the port is open. You should remove http from the supported services, as it is really misleading,
or implement a real check. It should do a GET for '/' , and validate that

• the answer comes from a web server (HTTP...)
• and that the answer is OK (in the range 2xx or 3xx) .

For my implementation, web scenarios are too heavywheight and not enougth integrated with the templating system to be useful.