Add support for the age_add field

Update SSL_SESSION to store the age_add and use it where needed.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2259)
diff --git a/ssl/ssl_asn1.c b/ssl/ssl_asn1.c
index 401aeb5..ced6a51 100644
--- a/ssl/ssl_asn1.c
+++ b/ssl/ssl_asn1.c
@@ -55,6 +55,7 @@
     long verify_result;
     ASN1_OCTET_STRING *tlsext_hostname;
     long tlsext_tick_lifetime_hint;
+    long tlsext_tick_age_add;
     ASN1_OCTET_STRING *tlsext_tick;
 #ifndef OPENSSL_NO_PSK
     ASN1_OCTET_STRING *psk_identity_hint;
@@ -89,7 +90,8 @@
 #ifndef OPENSSL_NO_SRP
     ASN1_EXP_OPT(SSL_SESSION_ASN1, srp_username, ASN1_OCTET_STRING, 12),
 #endif
-    ASN1_EXP_OPT(SSL_SESSION_ASN1, flags, ZLONG, 13)
+    ASN1_EXP_OPT(SSL_SESSION_ASN1, flags, ZLONG, 13),
+    ASN1_EXP_OPT(SSL_SESSION_ASN1, tlsext_tick_age_add, ZLONG, 14)
 } static_ASN1_SEQUENCE_END(SSL_SESSION_ASN1)
 
 IMPLEMENT_STATIC_ASN1_ENCODE_FUNCTIONS(SSL_SESSION_ASN1)
@@ -190,6 +192,7 @@
     }
     if (in->ext.tick_lifetime_hint > 0)
         as.tlsext_tick_lifetime_hint = in->ext.tick_lifetime_hint;
+    as.tlsext_tick_age_add = in->ext.tick_age_add;
 #ifndef OPENSSL_NO_PSK
     ssl_session_sinit(&as.psk_identity_hint, &psk_identity_hint,
                       in->psk_identity_hint);
@@ -326,6 +329,7 @@
 #endif
 
     ret->ext.tick_lifetime_hint = as->tlsext_tick_lifetime_hint;
+    ret->ext.tick_age_add = as->tlsext_tick_age_add;
     if (as->tlsext_tick) {
         ret->ext.tick = as->tlsext_tick->data;
         ret->ext.ticklen = as->tlsext_tick->length;