[1343] make sure changed named_set is stored when removing element

this bug resulted in the symptom that when removing from the default value, the removal wasn't stored

src/lib/python/isc/config/ccsession.py

@@ -543,6 +543,7 @@ class UIModuleCCSession(MultiConfigData):
                 cur_map = {}
             if value in cur_map:
                 del cur_map[value]
+                self.set_value(identifier, cur_map)
             else:
                 raise isc.cc.data.DataNotFoundError(value + " not found in named_set " + str(identifier))
 

src/lib/python/isc/config/tests/ccsession_test.py

@@ -756,6 +756,17 @@ class TestUIModuleCCSession(unittest.TestCase):
         uccs = self.create_uccs_named_set(fake_conn)
         value, status = uccs.get_value("/Spec32/named_set_item")
         self.assertEqual({'a': 1, 'b': 2}, value)
+
+        # make sure that removing from default actually removes it
+        uccs.remove_value("/Spec32/named_set_item", "a")
+        value, status = uccs.get_value("/Spec32/named_set_item")
+        self.assertEqual({'b': 2}, value)
+        self.assertEqual(uccs.LOCAL, status)
+
+        # ok, put it back now
+        uccs.add_value("/Spec32/named_set_item", "a")
+        uccs.set_value("/Spec32/named_set_item/a", 1)
+
         uccs.add_value("/Spec32/named_set_item", "foo")
         value, status = uccs.get_value("/Spec32/named_set_item")
         self.assertEqual({'a': 1, 'b': 2, 'foo': 3}, value)