Remove reference to no longer existing file win32.c

Change-Id: If010fa135fe9cb32602a58d2ad03198a79409205
Reviewed-on: http://review.couchbase.org/24602
Reviewed-by: Aaron Miller <apage43@ninjawhale.com>
Tested-by: Filipe David Borba Manana <fdmanana@gmail.com>