[FIX] Bug report: ufw: interface option causes an error (1.9.4) (ansible#1491) (ansible#2668)

Author: ovcharenko

system/ufw.py

@@ -225,7 +225,7 @@ def execute(cmd):
     if len(commands) < 1:
         module.fail_json(msg="Not any of the command arguments %s given" % commands)
 
-    if('interface' in params and 'direction' not in params):
+    if('interface' in params and params['direction'] is None):
       module.fail_json(msg="Direction must be specified when creating a rule on an interface")
 
     # Ensure ufw is available