Ignore win32 build artifacts

Change-Id: I53734cf77f2c301ec8c2fc877d384797f588d30a
Reviewed-on: http://review.couchbase.org/31414
Reviewed-by: Trond Norbye <trond.norbye@gmail.com>
Tested-by: Trond Norbye <trond.norbye@gmail.com>