scripted-diff: test: replace command with msgtype

This is the functional test framework pendant for
7777e3624f, which renamed "strCommand" with
"msg_type" in the network processing code.

-BEGIN VERIFY SCRIPT-
 # Rename in test framework
 sed -i 's/command/msgtype/g' ./test/functional/test_framework/messages.py ./test/functional/test_framework/mininode.py
 # Rename in individual tests
 sed -i 's/command/msgtype/g' ./test/functional/p2p_invalid_messages.py ./test/functional/p2p_leak.py
-END VERIFY SCRIPT-

test/functional/p2p_leak.py

@@ -37,7 +37,7 @@ class CLazyNode(P2PInterface):
 
     def bad_message(self, message):
         self.unexpected_msg = True
-        self.log.info("should not have received message: %s" % message.command)
+        self.log.info("should not have received message: %s" % message.msgtype)
 
     def on_open(self):
         self.ever_connected = True