Fix for bug that would make Nmap fail to run when compile without SSL support.

The wsdd library incorrectly assumed OpenSSL to always be available and the
ssh-hostkey used the undeclared SCRIPT_NAME in message when evaluating SSL
support. The bug was reported by Michael Pattrick on nmap-dev:
http://seclists.org/nmap-dev/2011/q1/312

[Patrik]

scripts/ssh-hostkey.nse

@@ -51,7 +51,7 @@ else
   portrule = function() return false end
   action = function() end
   stdnse.print_debug( 3, "Skipping %s script because OpenSSL is missing.",
-      SCRIPT_NAME)
+      filename)
   return;
 end