It was possible for the Action frame used for entring WNM Sleep Mode to
get dropped on the AP side due to it arriving prior to having processed
EAPOL-Key message 4/4 due to a race condition between Data and
Management frame processing paths. Avoid this by waiting for
AP-STA-CONNECTED event from hostapd prior to trying to enter WNM Sleep
Mode. In addition, make the check for the STA flag change more robust by
allowing the wait to be a bit longer with a loop that terminates as soon
as the flag has changed.
Signed-off-by: Jouni Malinen <j@w1.fi>