Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

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

MFH (r237568, r255422, r255460, r255766, r255767, r255774, r255829,
r256126, r257954, r261320, r261499, r263691, r263712): upgrade to
OpenSSH 6.6p1 via 6.3p1, 6.4p1 and 6.5p1.

Differences relative to head:

- No DNSSEC support since stable/9 does not have LDNS
- Sandboxing off by default, and uses rlimit instead of Capsicum
- ED25519 moved to the bottom of the order of preference to avoid
"new public key" warnings

These three files appeared in 6.0p1, which was imported into the vendor
branch but never merged to head. They were inadvertantly left out when
6.1p1 was merged to head. It didn't make any difference at the time,
because they were unused, but one of them is required for DNS-based host
key verification.

Approved by: re (blanket)

Vendor import of OpenSSH 6.2p1.

Vendor import of OpenSSH 6.1p1.

Remove autoprops :(

Vendor import of OpenSSH 6.0p1.