dirmngr: Load the hosts file into libdns.

dirmngr: Load the hosts file into libdns.

* dirmngr/dns-stuff.c (libdns_init): Actually load the hosts file into
libdns.
--

Previously, connecting to key servers specified in /etc/hosts was not
possible because libdns' hosts structure was initialized, but not
filled with the content of the hosts file.

GnuPG-bug-id: 2977
Signed-off-by: Justus Winter <justus@g10code.com>
(cherry picked from commit 88f1505f0613894d5544290a170119eb538921e5)

Gbp-Pq: Name 0053-dirmngr-Load-the-hosts-file-into-libdns.patch