Update to r39206:
- ipv6_enable is deprecated; use ip6_prefer instead.
- ipv6_ifconfig_{interface} is deprecated in favor of
  ifconfig_{interface}_ipv6; additionally, the latter requires the
  specification of 'inet6'.

Submitted by:	Bjoern Heidotting
Obtained from:	The FreeBSD German Documentation Project
Update to r38790:
Indicate that the interface is appended to the filename.

Submitted by:	Bjoern Heidotting
Obtained from:	The FreeBSD German Documentation Project