Reset s->tlsext_ticket_expected in ssl_scan_serverhello_tlsext.
This ensures that it's zeroed even if the SSL object is reused
(as in ssltest.c). It also ensures that it applies to DTLS, too.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit a06cd5d056c6a5b1d161786873e21a5e53d554d8)
Set s->hit when resuming from external pre-shared secret.

The same change was independently made in BoringSSL, see commit
9eaeef81fa2d4fd6246dc02b6203fa936a5eaf67

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 7b3ba508af5c86afe43e28174aa3c53a0a24f4d9)
Remove ssl3_check_finished.

The client sends a session ID with the session ticket, and uses
the returned ID to detect resumption, so we do not need to peek
at handshake messages: s->hit tells us explicitly if we're resuming.

An equivalent change was independently made in BoringSSL, see commit
407886f589cf2dbaed82db0a44173036c3bc3317.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit 980bc1ec6114f5511b20c2e6ca741e61a39b99d6)

Conflicts:
	ssl/d1_clnt.c
	ssl/s3_clnt.c
Always require an advertised NewSessionTicket message.

The server must send a NewSessionTicket message if it advertised one
in the ServerHello, so make a missing ticket message an alert
in the client.

An equivalent change was independently made in BoringSSL, see commit
6444287806d801b9a45baf1f6f02a0e3a16e144c.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit de2c7504ebd4ec15334ae151a31917753468f86f)

Conflicts:
	CHANGES
Ensure SSL3_FLAGS_CCS_OK (or d1->change_cipher_spec_ok for DTLS) is reset
once the ChangeCipherSpec message is received. Previously, the server would
set the flag once at SSL3_ST_SR_CERT_VRFY and again at SSL3_ST_SR_FINISHED.
This would allow a second CCS to arrive and would corrupt the server state.

(Because the first CCS would latch the correct keys and subsequent CCS
messages would have to be encrypted, a MitM attacker cannot exploit this,
though.)

Thanks to Joeri de Ruiter for reporting this issue.

Reviewed-by: Matt Caswell <matt@openssl.org>
(cherry picked from commit e94a6c0ede623960728415b68650a595e48f5a43)

Conflicts:
	CHANGES
	ssl/s3_srvr.c