pyloxi: fix of_wc_bmap_t for OF 1.2+

This field changed semantics, so the LOXI type probably should change too.
diff --git a/py_gen/tests/of12.py b/py_gen/tests/of12.py
index a176253..b557730 100644
--- a/py_gen/tests/of12.py
+++ b/py_gen/tests/of12.py
@@ -157,9 +157,7 @@
         self.klasses.sort(key=lambda x: str(x))
 
     def test_serialization(self):
-        expected_failures = [
-            ofp.common.table_stats_entry,
-        ]
+        expected_failures = []
         for klass in self.klasses:
             def fn():
                 obj = klass()
@@ -173,9 +171,7 @@
                 fn()
 
     def test_show(self):
-        expected_failures = [
-            ofp.common.table_stats_entry,
-        ]
+        expected_failures = []
         for klass in self.klasses:
             def fn():
                 obj = klass()