bin/46579: ifconfig prints unnecessary message when deleting interface

[Takahiro HAYASHI <t-hash%abox3.so-net.ne.jp@localhost>]

>Number:         46579
>Category:       bin
>Synopsis:       ifconfig prints unnecessary message when deleting interface
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Jun 11 00:55:00 +0000 2012
>Originator:     Takahiro HAYASHI
>Release:        NetBSD 6.99.7
>Organization:
>Environment:
System: NetBSD ruin 6.99.7 NetBSD 6.99.7 (MONOLITHIC) #0: Sun May 27 10:16:46 
UTC 2012  
builds%b6.netbsd.org@localhost:/home/builds/ab/HEAD/i386/201205270250Z-obj/home/builds/ab/HEAD/src/sys/arch/i386/compile/MONOLITHIC
 i386
Architecture: i386
Machine: i386
>Description:
ifconfig(8) prints out unnecessary message and exits with 1 when
deleting interface.  The exit value `1' in such case is wrong
because the specified interface has been removed successfully.

# ifconfig tap0 create
# echo $?
0
# ifconfig tap0 destroy
tap0: detached
ifconfig: commit_address: getifinfo: Device not configured
# echo $?
1
# ifconfig tap0
ifconfig: SIOCGIFFLAGS tap0: Device not configured
# echo $?
1
# 

It works correctly before rev 1.15 of src/sbin/ifconfig/af_inetany.c.

# ifconfig tap0 create
# echo $?
0
# ifconfig tap0 destroy
tap0: detached
# echo $?
0
# ifconfig tap0
ifconfig: SIOCGIFFLAGS tap0: Device not configured
# echo $?
1
# 

>How-To-Repeat:
Please see Description.
>Fix:
No idea.