Fix: drush-ops/drush#894 Super quick, insecure and dirty solution for now. You shouldn't use.
File ./includes/drush.inc, add --no-check-certificate
for wget command, --insecure
for curl command.
// ...
if ($use_wget) {
drush_shell_exec("wget --no-check-certificate -q --timeout=30 -O %s %s", $destination_tmp, $url);
}
else {