This is a memory error for anything other than LHASH_OF(char), which
does not exist.

No code outside the library creates (or even queries) an LHASH, so we
can change this module freely.

Change-Id: Ifbc7a1c69a859e07650fcfaa067bdfc68d83fbbc
Reviewed-on: https://boringssl-review.googlesource.com/12978
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>