ssl: fix handshake cert buffer sizing

'trec' buffer was not grown properly when it was checked as too small.
After this it wasn't checked again so that copying into the buffer could
overflow it.

src/app-layer-ssl.c

@@ -1408,7 +1408,7 @@ static int SSLv3ParseHandshakeType(SSLState *ssl_state, const uint8_t *input,
             if (ssl_state->curr_connp->trec_pos + input_len >=
                     ssl_state->curr_connp->trec_len) {
                 ssl_state->curr_connp->trec_len =
-                        ssl_state->curr_connp->trec_len + 2 * input_len + 1;
+                        ssl_state->curr_connp->trec_pos + 2 * input_len + 1;
                 ptmp = SCRealloc(ssl_state->curr_connp->trec,
                         ssl_state->curr_connp->trec_len);