docs/162354: Improve wording in rc.conf(5) regarding network-interfaces.

[moritz at wzff.de]

>Number:         162354
>Category:       docs
>Synopsis:       Improve wording in rc.conf(5) regarding network-interfaces.
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-doc
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          doc-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Nov 07 19:00:22 UTC 2011
>Closed-Date:
>Last-Modified:
>Originator:     Moritz Wilhelmy
>Release:        FreeBSD 9.0-RC1 amd64
>Organization:
>Environment:
>Description:
	According to rc.conf(5), ifconfig_<interface>_alias<n> is deprecated,
	because it fails if <n> is not continuously increasing (i.e. if a number is
	missing, the rc-scripts abort the search for bigger values of <n>.)
	It isn't specified what should be used instead; I guessed
	ipv4_addrs_<interface>, but Marco Steinbach brought
	/etc/start_if.<interface> to my attention, which is mentioned in the same
	paragraph. This is confusing. Could someone please clarify which one of
	these is supposed to be used in place of the deprecated
	ifconfig_<interface>_alias<n>, especially since ipv4_addrs_<interface> seems
	not to have an equivalent ipv6_* variable?
>How-To-Repeat:
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted: