Use shortport.http where appropriate.

scripts/http-headers.nse

@@ -31,20 +31,7 @@ categories = {"discovery", "safe"}
 require "shortport"
 require "http"
 
-portrule = function(host, port)
-	local svc = { std = { ["http"] = 1, ["http-alt"] = 1 },
-				ssl = { ["https"] = 1, ["https-alt"] = 1 } }
-	if port.protocol ~= 'tcp'
-	or not ( svc.std[port.service] or svc.ssl[port.service] ) then
-		return false
-	end
-	-- Don't bother running on SSL ports if we don't have SSL.
-	if (svc.ssl[port.service] or port.version.service_tunnel == 'ssl')
-	and not nmap.have_ssl() then
-		return false
-	end
-	return true
-end
+portrule = shortport.http
 
 action = function(host, port)
 	local path = nmap.registry.args.path