1) ignore probe requests rather than printing "unknown mgmt subtype"
(cosmetic)
2) don't panic if mget of the 2nd mbuf in a chain fails (patch from MCR)
(though that whole function badly needs to be rewritten)
3) be a little more tenacious about hanging on to an access point.
Working well enough to support dhcp; i'm doing this commit using the
interface.
Supports FH only. Does not yet do ad-hoc mode; works in
infrastructure mode. Not yet tested in environments with multiple
access points.
