Traceback (most recent call last):
  ...
  File "neo/lib/handler.py", line 72, in dispatch
    method(conn, *args, **kw)
  File "neo/master/handlers/client.py", line 70, in askFinishTransaction
    conn.getPeerId(),
  File "neo/master/transactions.py", line 387, in prepare
    assert node_list, (ready, failed)
AssertionError: (set([]), frozenset([]))

Master log leading to the crash:
  PACKET    #0x0009 StartOperation                 > S1
  PACKET    #0x0004 BeginTransaction               < C1
  DEBUG     Begin <...>
  PACKET    #0x0004 AnswerBeginTransaction         > C1
  PACKET    #0x0001 NotifyReady                    < S1

It was wrong to process BeginTransaction before receiving NotifyReady.

The changes in the storage are cosmetics: the 'ready' attribute has become
redundant with 'operational'.