Although the previous commit should ensure this doesn't happen, the
uint8_t** pattern is very error-prone and we're trying to avoid doing
much to the legacy ASN.1 stack. To that end, maintaining the strong
exception guarantee w.r.t. the input pointer-pointer is best effort and
we won't rely on it, so we needn't spend our time chasing down problems.
Change-Id: Ib78974eb94377fe0b0b379f57d9695dc81f344bb
Reviewed-on: https://boringssl-review.googlesource.com/5949
Reviewed-by: Adam Langley <agl@google.com>
382bc29251