message: Fix exception in create_account
diff: @@ -226,7 +226,7 @@ def create_account(creator, newaccount, owner_key, active_key, sign=True):
  sign = 0
  result, cost = create_account_(creator, newaccount, owner_key, active_key, sign)
  - if result[0]:
  + if result:
  return JsonStruct(result[0])
  return None
  