various improvement

- improve change log entry
- improve comments
- remove unnecessary statement
- change type of client_age

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index f85bc1a..c96128b 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -1430,14 +1430,14 @@
                                             (7 * 24 * 3600 * 1000 + 1000);
             break;
         case 5:
-            /* Ticket is valid, but client age is below the upper bound of tolerance window. */
+            /* Ticket is valid, but client age is below the lower bound of the tolerance window. */
             session->ticket_age_add += MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE + 4 * 1000;
             /* Make sure the execution time does not affect the result */
             session->ticket_creation_time = mbedtls_ms_time();
             break;
 
         case 6:
-            /* Ticket is valid, but client age is beyond the lower bound of tolerance window. */
+            /* Ticket is valid, but client age is beyond the upper bound of the tolerance window. */
             session->ticket_age_add -= MBEDTLS_SSL_TLS1_3_TICKET_AGE_TOLERANCE + 4 * 1000;
             /* Make sure the execution time does not affect the result */
             session->ticket_creation_time = mbedtls_ms_time();