check prefs file perms on windows

[scottdraves]

https://github.com/twosigma/beakerx/blob/master/beakerx/beakerx/install.py#L134

beakerx/beakerx/beakerx/environment.py

Line 43 in 2fb631e

with fdopen(osopen(EnvironmentSettings.config_path, O_RDWR | O_CREAT | O_TRUNC, 0o600), 'w+') as file:

we need to check if these actually work on windows.
i am pretty sure chmod is just ignored.
not sure about the os.open.

[jmsdnns]

Possibly relevant: https://stackoverflow.com/questions/12168110/setting-folder-permissions-in-windows-using-python