When a low level driver calls cfg80211_disconnected(), wep keys are
not cleared. As a result, following connection requests will fail
since cfg80211 internal state shows a connection is still in progress.

Fix this by clearing the wep keys when disconnecting.
Signed-off-by: NAvraham Stern <avraham.stern@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>
Signed-off-by: NJohannes Berg <johannes.berg@intel.com>