Spyder: In ipdb, the up and down keys have a strange behaviour

Description

What steps will reproduce the problem?

1. debug
2. press up to access the last thing you typed
3. wonder why you ended up in the middle of the history log

Version and main components

• Spyder Version: 3.2.4.dev0 474e59379
• Python Version: 3.6.2
• Qt Versions: 5.9.1, PyQt5 5.9 on Darwin

Dependencies

pyflakes >=0.6.0 :  1.6.0 (OK)
pycodestyle >=2.3:  2.3.1 (OK)
pygments >=2.0   :  2.2.0 (OK)
pandas >=0.13.1  :  0.20.3 (OK)
numpy >=1.7      :  1.13.1 (OK)
sphinx >=0.6.6   :  1.6.3 (OK)
rope >=0.9.4     :  0.10.5 (OK)
jedi >=0.9.0     :  0.10.2 (OK)
psutil >=0.3     :  5.2.2 (OK)
nbconvert >=4.0  :  5.2.1 (OK)
sympy >=0.7.3    :  1.1.1 (OK)
cython >=0.21    :  0.26 (OK)
qtconsole >=4.2.0:  4.3.0 (OK)
IPython >=4.0    :  6.1.0 (OK)
pylint >=0.25    :  1.7.2 (OK)