Handle compression methods correctly with SSLv2 compat ClientHello

In the case of an SSLv2 compat ClientHello we weren't setting up the
compression methods correctly, which could lead to uninit reads or crashes.
Reviewed-by: NKurt Roeckx <kurt@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>

ssl/statem/statem_srvr.c

@@ -1039,10 +1039,7 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
             goto f_err;
         }
 
-        if (!PACKET_get_length_prefixed_1(pkt, &compression)
-                || !PACKET_copy_all(&compression, clienthello.compressions,
-                               MAX_COMPRESSIONS_SIZE,
-                               &clienthello.compressions_len)) {
+        if (!PACKET_get_length_prefixed_1(pkt, &compression)) {
             al = SSL_AD_DECODE_ERROR;
             SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
             goto f_err;
@@ -1060,9 +1057,11 @@ MSG_PROCESS_RETURN tls_process_client_hello(SSL *s, PACKET *pkt)
         }
     }
 
-    if (!PACKET_copy_all(&session_id, clienthello.session_id,
-                         SSL_MAX_SSL_SESSION_ID_LENGTH,
-                         &clienthello.session_id_len)) {
+    if (!PACKET_copy_all(&compression, clienthello.compressions,
+                         MAX_COMPRESSIONS_SIZE, &clienthello.compressions_len)
+            || !PACKET_copy_all(&session_id, clienthello.session_id,
+                                SSL_MAX_SSL_SESSION_ID_LENGTH,
+                                &clienthello.session_id_len)) {
         al = SSL_AD_DECODE_ERROR;
         SSLerr(SSL_F_TLS_PROCESS_CLIENT_HELLO, SSL_R_LENGTH_MISMATCH);
         goto f_err;