Unexpected BUG violation in hsv3 decriptor decoding

As you can see in hs_descriptor.c

  /* Find the start of signature. */
  sig_start = tor_memstr(encoded_desc, encoded_len, "\n" str_signature);
  /* Getting here means the token parsing worked for the signature so if we
   * can't find the start of the signature, we have a code flow issue. */
  if (BUG(!sig_start)) {
    goto err;
  }

str_signature is "signature", so, if you send the "\n signature" (like in the attachment) instead of "\nsignature" tor_memstr will return null and violate BUG(!sig_start)

I suggest that we should just remove BUG and let it be if (!sig_start) {