dirmngr: Let --gpgconf-list return the default keyserver.

* dirmngr/misc.c (get_default_keyserver): New.
* dirmngr/http.c: Include misc.h
(http_session_new): Use get_default_keyserver instead of hardwired
"hkps.pool.sks-keyservers.net".
* dirmngr/http-ntbtls.c (gnupg_http_tls_verify_cb): Ditto.
* dirmngr/dirmngr.c (main) <aGPGCongList>: Return default keyserver.

Signed-off-by: Werner Koch <wk@gnupg.org>

dirmngr/misc.h

@@ -21,6 +21,8 @@
 #ifndef MISC_H
 #define MISC_H
 
+const char *get_default_keyserver (int name_only);
+
 /* Convert hex encoded string back to binary. */
 size_t unhexify (unsigned char *result, const char *string);