message: [tests] Make mininode_lock non-reentrant
  There's no need for mininode_lock to be reentrant.
  Use a simpler non-recursive lock.
diff: @@ -492,7 +492,7 @@ class P2PInterface(P2PConnection):
  # P2PConnection acquires this lock whenever delivering a message to a P2PInterface.
  # This lock should be acquired in the thread running the test logic to synchronize
  # access to any data shared with the P2PInterface or P2PConnection.
  -mininode_lock = threading.RLock()
  +mininode_lock = threading.Lock()
  class NetworkThread(threading.Thread):
  