doh: fix cleanup

When removing an easy handle that had DoH sub-easy handles going, those
were not removed from the multi handle. Their memory was reclaimed on
curl_easy_cleanup() of the owning handle, but multi still had them in
their list.

Add `Curl_doh_close()` and `Curl_doh_cleanup()` as common point for
handling the DoH resource management. Use the `multi` present in the doh
handles (if so), for removal, as the `data->multi` might already have
been NULLed at this time.

Reported-by: 罗朝辉
Fixes #14207
Closes #14212

0 files changed, 0 insertions, 0 deletions