Previously, code using directly (guix build download) was still affected
by <http://bugs.gnu.org/15368>. This includes source derivations, the
'guix download' command, and (guix gnu-maintenance).
'guix substitute' was unaffected since it used (guix http-client), which
already had the fix.
* guix/http-client.scm (open-socket-for-uri): Remove.
(http-fetch): Remove #:buffered? argument to 'open-socket-for-uri';
use 'setvbuf' instead.
* guix/scripts/substitute.scm (fetch): Likewise.
* guix/build/download.scm (open-socket-for-uri): New procedure, taken
from guix/http-client.scm, but without the #:buffered? parameter.
In practice we would not leak much since we reconnect after ~100
requests (with nginx running on hydra.gnu.org.)
* guix/scripts/substitute.scm (http-multiple-get): Call 'close-port'
before 'connect'.