Clean up imports to be pyflakes-checkable. fixes #2450

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

qa/rpc-tests/maxblocksinflight.py

@@ -4,9 +4,15 @@
 # file COPYING or http://www.opensource.org/licenses/mit-license.php.
 #
 
-from test_framework.mininode import *
+from test_framework.mininode import NodeConn, NodeConnCB, NetworkThread, \
+    EarlyDisconnectError, CInv, msg_inv, mininode_lock
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.util import *
+from test_framework.util import initialize_chain_clean, start_nodes, \
+    p2p_port
+
+import os
+import time
+import random
 import logging
 
 '''