FAIL: traitsui.tests.test_splitter_prefs_restored.test_splitter_prefs_are_restored

Seen on a Windows 10 machine running using python 3.5.2 and pyqt5

```python
======================================================================
FAIL: traitsui.tests.test_splitter_prefs_restored.test_splitter_prefs_are_restored
----------------------------------------------------------------------
Traceback (most recent call last):
File "C:\Users\...\.edm\envs\traitsui-test-3.5-pyqt5\lib\site-packages\nose\case.py", line 198, in runTest
self.test(*self.arg)
File "C:\Users\...\.edm\envs\traitsui-test-3.5-pyqt5\lib\site-packages\traitsui-5.2.0.dev356-py3.5.egg\traitsui\tests\_tools.py", line 88, in wrapper
return item(*args, **kwargs)
File "C:\Users\...\.edm\envs\traitsui-test-3.5-pyqt5\lib\site-packages\traitsui-5.2.0.dev356-py3.5.egg\traitsui\tests\test_splitter_prefs_restored.py", line 136, in test_splitter_prefs_are_restored
_get_nattr(ui2.get_prefs()))
AssertionError: b'\x0[54 chars]x00\x00\x00\x00\x02M\x01\xff\xff\xff\xff\x00\x[14 chars]\x01' != b'\x0[54 chars]x00\x89\x00\x00\x02"\x01\xff\xff\xff\xff\x00\x[14 chars]\x01'
```