[PATCH v2 2/2] debuginfod-client.c: Fix x-debuginfod-size counts differently than CURLINFO_SIZE_DOWNLOAD_T

[Frank Ch. Eigler]

Hi -

> x-debuginfod-size is the actual file size, but CURLINFO_SIZE_DOWNLOAD_T
> is transferred size, i.e. the gzipped one if gzip is on.
> Let's count written data and use that if and only if x-debuginfod-size
> is used.

Hey, great idea actually tallying up writes in the callback function.
(We need to take care to clear that counter, in case of client object
reuse.)  Also, can you think of some reason not to just use that value
at all times, i.e., without any of that "if and only if ..." business?

- FChE