Fix fallback from failed PMKSA caching into full EAP authentication (DO NOT MERGE)

Fix fallback from failed PMKSA caching into full EAP authentication (DO NOT MERGE)

Commit 83935317a78fb4157eb6e5134527b9311dbf7b8c added forced
disconnection in case of 4-way handshake failures. However, it should
not have changed the case where the supplicant is requesting fallback
to full EAP authentication if the PMKID in EAPOL-Key message 1/4 is
not know. This case needs to send an EAPOL-Start frame instead of
EAPOL-Key message 2/4.

This works around a problem with APs that try to force PMKSA caching
even when the client does not include PMKID in (re)association request
frame to request it. [Bug 355]

Change-Id: Ib0175ccddbc961583b2662abc1e21c95927b084a
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>