dirmngr: Fix the regression of use of proxy for TLS connection.
* dirmngr/http.c (run_proxy_connect): Don't set keep_alive, since it causes resource leak of FP_WRITE. Don't try to read response body to fix the hang.
- GnuPG-bug-id: T6997
- Signed-off-by: NIIBE Yutaka <gniibe@fsij.org>