calls pututxline() with ruid = 0, euid = current-ftp-user. This ends
up calling update_utmp:
- if the real uid is root, don't do password or tty ownership checks
- if we cannot open the tty line, assume that it is a daemon that does
not use ttys and allow it to change a live entry to a dead one if
indeed it is the same process that created the entry.
christos