[MERGE] Implement bzrlib.lock with CreateFile rather than LockFileEx on win32 (operational part)

[Martin Pool]

Martin Pool has voted approve.
Status is now: Semi-approved
Comment:
OK, it doesn't actually break unix.

It should be mentioned in NEWS, including whether this makes it any 
faster or more robust, or is just cleaner.

I'd like to hear from Alexander or another win32 expert before merging 
it.

For details, see: 
http://bundlebuggy.aaronbentley.com/project/bzr/request/%3Cd80792120906181039o67270d1fy78d777b7c681f3ee%40mail.gmail.com%3E
Project: Bazaar