[2225_xfrout] changed the test condition for "socket/unixdomain/open" counter of Xfrout

because its counter would probably return 0 or 1 depending on timing

tests/lettuce/features/xfrin_notify_handling.feature

@@ -39,7 +39,7 @@ Feature: Xfrin incoming notify handling
     Then the statistics counter axfr_running should be 0
 
     When I query statistics socket of bind10 module Xfrout with cmdctl port 47804
-    Then the statistics counter open should be 0
+    Then the statistics counter open should be between 0 and 1
     Then the statistics counter openfail should be 0
     Then the statistics counter close should be 0
     Then the statistics counter bindfail should be 0