print error on stderr

git-svn-id: svn+ssh://svn.code.sf.net/p/migrid/code/trunk@6080 b75ad72c-e7d7-11dd-a971-7dbc132099af

Author: jonasbardino

mig/server/genoiddiscovery.py

@@ -107,7 +107,7 @@ def usage(name='genoiddiscovery.py'):
         print(generate_openid_discovery_doc(configuration))
         retval = 0
     except Exception as err:
-        print(err)
+        print(err, file=sys.stderr)
         sys.exit(1)
 
     sys.exit(retval)