cfg80211/mac80211 can get into somewhat confused state if the AP only
disassociates us and leaves us in authenticated state. For now, force
the state to be cleared with deauthentication to avoid confusing errors
if we try to associate with the AP again. This gets rid of 30 second
delay (scan timeout) in cases where only a disassociation frame is
received from the AP.
This can be used, e.g., with mac80211-based Linux drivers with
nl80211. This allows over-the-air FT protocol to be used (IEEE
802.11r).
Since the nl80211 interface needed for this is very recent (added
today into wireless-testing.git), driver_nl80211.c has backwards
compatibility code that uses WEXT for association if the kernel does
not support the new commands. This compatibility code can be
disabled by defining NO_WEXT_COMPAT. That code will also be removed
at some point to clean up driver_nl80211.c.
