test: remove necessity to call create_callback_map

Remove necessity to call create_callback_map (as well as the function
itself) from the Python P2P test framework. Invoke the appropriate
methods directly.

- Easy to forget to call it and wonder why it doesn't work
- Simplifies the code
- This makes it easier to handle new messages in subclasses

qa/rpc-tests/test_framework/mininode.py

@@ -1015,32 +1015,10 @@ class NodeConnCB(object):
                     return
             time.sleep(0.05)
 
-    # Derived classes should call this function once to set the message map
-    # which associates the derived classes' functions to incoming messages
-    def create_callback_map(self):
-        self.cbmap = {
-            "version": self.on_version,
-            "verack": self.on_verack,
-            "addr": self.on_addr,
-            "alert": self.on_alert,
-            "inv": self.on_inv,
-            "getdata": self.on_getdata,
-            "getblocks": self.on_getblocks,
-            "tx": self.on_tx,
-            "block": self.on_block,
-            "getaddr": self.on_getaddr,
-            "ping": self.on_ping,
-            "pong": self.on_pong,
-            "headers": self.on_headers,
-            "getheaders": self.on_getheaders,
-            "reject": self.on_reject,
-            "mempool": self.on_mempool
-        }
-
     def deliver(self, conn, message):
         with mininode_lock:
             try:
-                self.cbmap[message.command](conn, message)
+                getattr(self, 'on_' + message.command)(conn, message)
             except:
                 print "ERROR delivering %s (%s)" % (repr(message),
                                                     sys.exc_info()[0])