EAP server: Force identity request after INITIALIZE for passthrough

EAP server: Force identity request after INITIALIZE for passthrough

Previously, sm->start_reauth was set to TRUE in SUCCESS2 state to force
reauthentication to start with EAP identity request. This works fine for
the case of EAP success through the AAA passthrough authentication, but
is not enough to handle passthrough authentication failure. sm->identity
is set in that case and getDecision would return PASSTHROUGH instead of
CONTINUE (to Identity method).

Signed-hostap: Jouni Malinen <j@w1.fi>