Fix unhandled error condition in sslv2 client hello parsing.

--strict-warnings started showing warnings for this today...

Surely an error should be raised if these reads fail?
Reviewed-by: NTim Hudson <tjh@openssl.org>
Reviewed-by: NMatt Caswell <matt@openssl.org>

ssl/s3_srvr.c

@@ -1014,6 +1014,9 @@ int ssl3_get_client_hello(SSL *s)
         if (!PACKET_get_net_2(&pkt, &csl)
                 || !PACKET_get_net_2(&pkt, &sil)
                 || !PACKET_get_net_2(&pkt, &cl)) {
+            SSLerr(SSL_F_SSL3_GET_CLIENT_HELLO, SSL_R_LENGTH_TOO_SHORT);
+            al = SSL_AD_DECODE_ERROR;
+            goto f_err;
         }
 
         if (csl == 0) {