Upgrade OpenSSH to 7.3p1.

This is the last version of OpenSSH which does not break compatibility
more than we can live with in a stable branch. Further commits will
follow to backport some bug fixes from newer versions.

The sshd breakage in the previous attempt was due to an upstream bug
(a 0 was changed to a 1 while refactoring send_rexec_state() in sshd.c)
which only manifested itself when sshd was built with SSH 1 support.

Approved by: re@

Revert OpenSSH 7.3p1; something went wrong between testing and committing.

Approved by: re@

Upgrade OpenSSH to 7.3p1.

This is the last version of OpenSSH which does not break compatibility
more than we can live with in a stable branch. Further commits will
follow to backport some bug fixes from newer versions.

Approved by: re@

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Upgrade to OpenSSH 5.1p1.

I have worked hard to reduce diffs against the vendor branch. One
notable change in that respect is that we no longer prefer DSA over
RSA - the reasons for doing so went away years ago. This may cause
some surprises, as ssh will warn about unknown host keys even for
hosts whose keys haven't changed.

MFC after: 6 weeks

Remove svn:keywords except on files that need it. This makes diffs
against the vendor branch much more readable.

Consistently set svn:eol-style.

This commit was generated by cvs2svn to compensate for changes in r162852,
which included commits to RCS files with non-trunk default branches.

Vendor import of OpenSSH 4.4p1.

Vendor import of OpenSSH 4.3p1.