text: Title: lie to the optimizer bug
  Body: Code:
  ```
  optimizer = Optimizer(dimensions=[[64, 128], (4, 1)])
  x = optimizer.ask(n_points=4)
  ```
  
  Note (4, 1) -> (1, 4)  also fails:
  ```
  optimizer = Optimizer(dimensions=[[64, 128], (1, 4)])
  x = optimizer.ask(n_points=4)
  ```
  
  Version:
  ```
  >>> skopt.__version__
  '0.4-dev'
  ```
  
  Traceback:
  ```
  Traceback (most recent call last):
    File "example/tune.py", line 188, in <module>
      main()
    File "example/tune.py", line 171, in main
      x = optimizer.ask(n_points=len(devices))
    File "/usr/local/lib/python3.5/dist-packages/skopt/optimizer/optimizer.py", line 336, in ask
      opt.tell(x, y_lie)  # lie to the optimizer
    File "/usr/local/lib/python3.5/dist-packages/skopt/optimizer/optimizer.py", line 396, in tell
      check_x_in_space(x, self.space)
    File "/usr/local/lib/python3.5/dist-packages/skopt/utils.py", line 192, in check_x_in_space
      % (x, space.bounds))
  ValueError: Point ([64, 2]) is not within the bounds of the space ([[64, 126, 252, 512], (4, 1)]).
  ```