RADIUS server: Increase maximum number of sessions

RADIUS server: Increase maximum number of sessions

It was possible to hit the previously used maximum of 100 active session
in some hwsim test case sequences like this one: eap_proto_pwd_errors
eap_proto_ikev2_errors eap_proto_sim_errors. This happened due to the
large number of RADIUS authentication iterations in short period of
time, i.e., within the 10 second timeout for expiring completed
sessions.

Increase RADIUS_MAX_SESSION from 100 to 1000 and also reduce the timeout
on expiring completed sessions from 10 to 5 seconds.

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