[session] fix a session copy bug
fix a possible double reference on 'ticket'
when peer_cert/peer_cert_digest calloc failed.

Signed-off-by: 吴敬辉 <11137405@vivo.com>
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 8195af2..41e6647 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -188,6 +188,10 @@
     mbedtls_ssl_session_free( dst );
     memcpy( dst, src, sizeof( mbedtls_ssl_session ) );
 
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
+    dst->ticket = NULL;
+#endif
+
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 
 #if defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)