Fixed issue with packet object and prepare()

If any part of the code had a packet object and called prepare()
on it, it would create a msgNo if it wasn't set.  Sometimes we
get packets on the wire/RF that don't have a msgNo, so adding one
locally is wrong.   We should ONLY create a msgNo on a packet that
is destined for transmission.

This patch ensures that even if prepare() is called, that only
packets that are created locally for TX get a msgNo unless it
already exists from RX'd packets.

tests/client/test_aprsis.py

@@ -61,7 +61,7 @@ class TestAPRSISClient(unittest.TestCase):
                     "connected": True,
                     "filter": "m/50",
                     "login_status": {"message": mock.ANY, "success": True},
-                    "server_keepalive": mock_client.aprsd_keepalive,
+                    "connection_keepalive": mock_client.aprsd_keepalive,
                     "server_string": mock_client.server_string,
                     "transport": "aprsis",
                 },

tests/cmds/test_webchat.py

@@ -8,6 +8,7 @@ import flask_socketio
 from oslo_config import cfg
 
 from aprsd import conf  # noqa: F401
+from aprsd.client import fake as fake_client
 from aprsd.cmds import webchat  # noqa
 from aprsd.packets import core
 
@@ -64,11 +65,13 @@ class TestSendMessageCommand(unittest.TestCase):
     @mock.patch("aprsd.threads.tx.send")
     @mock.patch("aprsd.packets.PacketList.rx")
     @mock.patch("aprsd.cmds.webchat.socketio")
+    @mock.patch("aprsd.client.factory.ClientFactory.create")
     def test_process_our_message_packet(
         self,
         mock_tx_send,
         mock_packet_add,
         mock_socketio,
+        mock_factory,
     ):
         self.config_and_init()
         mock_socketio.emit = mock.MagicMock()
@@ -77,6 +80,7 @@ class TestSendMessageCommand(unittest.TestCase):
             msg_number=1,
             message_format=core.PACKET_TYPE_MESSAGE,
         )
+        mock_factory.return_value = fake_client.APRSDFakeClient()
         mock_queue = mock.MagicMock()
         socketio = mock.MagicMock()
         wcp = webchat.WebChatProcessPacketThread(mock_queue, socketio)