The location of the ifconfig binary has changed in
net-tools-1.60_p20120127084908, and if we do not check both locations
for it, the user will get errors like:
_is_wireless: command not found
_exists: command not found
X-Gentoo-Bug: 407757
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=407757