(stop_transaction): Take "trans" HANDLE by reference and set it to
NULL after closing it.
(unlink_nt): If NtOpenFile fails due to a transactional error, stop
transaction and retry NtOpenFile. Simplify check for having to call
stop_transaction.
(rename): If NtOpenFile fails due to a transactional error, stop
transaction and retry NtOpenFile in both affected cases. Simplify check
for having to call stop_transaction and add comment from unlink_nt.
Corinna Vinschen
Christopher Faylor