Log Message:
Update to Net::SSH::Perl (here p5-Net-SSH) version 2.12.

Pkgsrc changes:
 * version number, checksum
 * Comment out WRKSRC manipulation, not needed for 2.12.

Upstream changes:

2.12 2017.04.22
    - Fix inefficiency in CTR, revealed by profiling with Devel::NYTProf
    - Avoid warnings in Host from strange/invalid known_host entries
    - Improve documentation of newer features

2.11 2017.04.16
    - Packet bugfix: Introduced in 2.07, when ETM Mac is used, sometimes
      not enough incoming bytes were available to fully read stored MAC
    - DSA key bugfix: verify would fail if r/s had highest bit set

2.10 2017.03.23
    - Add curve25519-sha256 alias for curve25519-sha256@libssh.org key exchange
    - Bugfix for when unsupported key types are encountered
    - Add support for '-' syntax in options, including wildcards
    - Add wildcard support for '+' syntax in options