It's fairly pointles to play with Unix rwxrwxrwx modes on Windows. One
never knows for sure how some emulation layer (Python's in this case)
guesstimates and mishandles the conversion to Windows ACLs. Not doing
them on Windows unbrokw the nss build. For me at least.

Change-Id: Id3a2f1755cd6f64bd681a3b4cb7f3c7abd3aa5b7