Bug 1428

Wanted: option to turn off Banner output for non-interactive
(remote command) sessions.  A banner may make the lawyers happy,
but is far more likely to be seen by an actual human with
interactive than with non-interactive use.  ssh -q option can
suppress this of course, but also suppresses potentially helpful
diagnostics.  Non-interactive banner output considerably clutters
error logs, cron job output, etc.; and postprocessing error logs to
remove such garbage is tedious and error prone, since the banners
may contain almost anything, be changed, etc.

Despite the arguable uselessness of banner output for non-interactive
sessions, there may be places with lawyers anal enough to insist on it.
Therefore, I suggest that suppressing it in that instance should be
an option rather than a change to default behavior (when Banner is set).
Making this a server option rather than a client option leaves the
server in control of policy, and implies no changes to protocol.