bind: only set bindfd after successful listen

In 'ssh_bind_listen', move setting of 'sshbind->bindfd' to only happen after
the listen call: otherwise 'bindfd' can be set to a bogus descriptor for the
case that listen fails.

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
packet: log disconnect code in host byte order

Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
server: silence build warning

The commit fixes this build warning:

====
src/server.c:223:8: warning: ‘privkey’ may be used uninitialized in this function [-Wmaybe-uninitialized]
     rc = ssh_pki_export_privkey_to_pubkey(*privkey, &pubkey);
        ^
src/server.c:243:11: note: ‘privkey’ was declared here
   ssh_key privkey;
====

Signed-off-by: Luka Perkov <luka.perkov@sartura.hr>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
pki: Use SHA-2 for session ID signing with ECDSA keys

Previously, SHA-1 was used always.

BUG: https://red.libssh.org/issues/148

Signed-off-by: Alan Dunn <amdunn@gmail.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
pki_crypto: Always copy ecdsa_nid into duplicated ECDSA keys

BUG: https://red.libssh.org/issues/147

Signed-off-by: Alan Dunn <amdunn@gmail.com>