kas: Don't return None from kas()

The return value of kas() is used as the argument to sys.exit() so it
should be 0 to report successful completion.

Signed-off-by: Paul Barker <pbarker@konsulko.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>

kas/kas.py

@@ -148,7 +148,7 @@ def kas(argv):
 
     for plugin in getattr(kasplugin, 'plugins', []):
         if plugin().run(args):
-            return
+            return 0
 
     parser.print_help()