o Visudo now locks the sudoers temp file instead of bailing when
the temp file already exists. This fixes the problem of stale
temp files but it does *require* that you not try to put the
temp file in a world-writable directory. This shoud not be
an issue as the temp file should live in the same dir as sudoers.
o Visudo now only installs the temp file as sudoers if it changed.
