[FIX] missing import in wsgi_server

bzr revid: xmo@openerp.com-20130313161815-rcupbzq08b2wst1j

openerp/service/wsgi_server.py

@@ -32,8 +32,7 @@ import StringIO
 
 import errno
 import logging
-import os
-import signal
+import platform
 import socket
 import sys
 import threading