bin/50847: complain if /usr/sbin/wpa_supplicant isn't present

[andrwe.cagney%gmail.com@localhost]

>Number:         50847
>Category:       bin
>Synopsis:       complain if /usr/sbin/wpa_supplicant isn't present
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    bin-bug-people
>State:          open
>Class:          change-request
>Submitter-Id:   net
>Arrival-Date:   Thu Feb 25 00:50:00 +0000 2016
>Originator:     Andrew Cagney
>Release:        7.99 ~ Feb 22, 2016
>Organization:
>Environment:
NetBSD rpi 7.99.26 NetBSD 7.99.26 (RPI) #0: Mon Feb 22 14:20:58 EST 2016  cagney@morgan:/home/cagney/NetBSD/trunk/evbearmv6hf-el/sys/arch/evbarm/compile/RPI evbarm

>Description:
When /usr isn't mounted and wpa_supplicant is enabled in rc.conf, things fail silently because:

                        if [ ! -x ${_chroot}${command} ]; then
                                return 0
                        fi

I think it should issue an informational message
>How-To-Repeat:
- set up a machine with separate /usr
- enable wpa_supplicant in rc.conf
- reboot
(yes, critical_filesystems_local should be missing)

wpa_supplicant doesn't start and there's nothing to hint at why.  Puzzlingly, running '/etc/rc.d/wpa_supplicant start' after boot works!
>Fix:
add a warn() call line vis:

                        if [ ! -x ${_chroot}${command} ]; then
                                warn {_chroot}${command} not found
                                return 0
                        fi

(BTW, is critical_filesystems_local normally set by the installer?)