master: fix identification of unknown masters

This fixes the following crash:

  Traceback (most recent call last):
    ...
    File "neo/master/handlers/identification.py", line 94, in requestIdentification
      uuid = app.getNewUUID(uuid, address, node_type)
    File "neo/master/app.py", line 449, in getNewUUID
      assert uuid != self.uuid
  AssertionError

neo/master/handlers/identification.py

@@ -49,7 +49,10 @@ class IdentificationHandler(EventHandler):
                         node = uuid = None
                         break
                 else:
-                    node.setAddress(address)
+                    if node is app._node:
+                        node = None
+                    else:
+                        node.setAddress(address)
                     break
                 # Id conflict for a storage node.
             else:

neo/tests/threaded/__init__.py

@@ -321,10 +321,10 @@ class ServerNode(Node):
         if not address:
             address = self.newAddress()
         if cluster is None:
-            master_nodes = kw.get('master_nodes', ())
+            master_nodes = ()
             name = kw.get('name', 'test')
         else:
-            master_nodes = kw.get('master_nodes', cluster.master_nodes)
+            master_nodes = cluster.master_nodes
             name = kw.get('name', cluster.name)
         port = address[1]
         if address is not BIND:

neo/tests/threaded/test.py

@@ -2319,6 +2319,21 @@ class Test(NEOThreadedTest):
         self.assertTrue(m0.primary)
         self.assertFalse(m2.primary)
 
+    @with_cluster(start_cluster=0, master_count=2)
+    def testIdentifyUnknownMaster(self, cluster):
+        m0, m1 = cluster.master_list
+        cluster.master_nodes = ()
+        m0.resetNode()
+        cluster.start(master_list=(m0,))
+        m1.start()
+        self.tic()
+        self.assertEqual(cluster.neoctl.getClusterState(),
+                         ClusterStates.RUNNING)
+        self.assertTrue(m0.primary)
+        self.assertTrue(m0.is_alive())
+        self.assertFalse(m1.primary)
+        self.assertTrue(m1.is_alive())
+
 
 if __name__ == "__main__":
     unittest.main()