Pull up following revision(s) (requested by nia in ticket #1406):

usr.sbin/sysinst/net.c: revision 1.40
usr.sbin/sysinst/msg.mi.pl: revision 1.37
usr.sbin/sysinst/msg.mi.fr: revision 1.36
usr.sbin/sysinst/msg.mi.de: revision 1.35
usr.sbin/sysinst/msg.mi.en: revision 1.37
usr.sbin/sysinst/net.c: revision 1.37
usr.sbin/sysinst/net.c: revision 1.38
usr.sbin/sysinst/msg.mi.es: revision 1.31
usr.sbin/sysinst/net.c: revision 1.39

sysinst(8): Add initial support for connecting to Wi-Fi networks
by spawning wpa_supplicant.
Reviewed by martin.

sysinst(8): Avoid asking Wi-Fi questions about non-Wi-Fi devices.

sysinst(8): Add a "data" argument to do_ifreq that is set after the
ifr struct is zeroed.

This allows us to simplify the code by not having 2x socket creation
code for checking whether interfaces are wireless.
sysinst(8): use scan_ssid=1 so hidden wifi networks can be used

(martin)