gpg: Print the actual used keyserver address.

* dirmngr/ks-engine-hkp.c (ks_hkp_search, ks_hkp_get): Print SOURCE
status lines.
* g10/call-dirmngr.c (ks_status_parm_s): New.
(ks_search_parm_s): Add field stparm.
(ks_status_cb): New.
(ks_search_data_cb): Send source to the data callback.
(gpg_dirmngr_ks_search): Change callback prototope to include the
SPECIAL arg.  Adjust all users.  Use ks_status_cb.
(gpg_dirmngr_ks_get): Add arg r_source and use ks_status_cb.
* g10/keyserver.c (search_line_handler): Adjust callback and print
"data source" disgnostic.
(keyserver_get): Print data source diagnostic.
--

It has often been requested that the actually used IP of a keyservers
is shown in with gpg --recv-key and --search-key.  This is helpful if
the keyserver is actually a pool of keyservers.  This patch does this.

dirmngr/ks-engine-hkp.c

@@ -454,8 +454,7 @@ mark_host_dead (const char *name)
 
 
 /* Mark a host in the hosttable as dead or - if ALIVE is true - as
-   alive.  If the host NAME does not exist a warning status message is
-   printed.  */
+   alive.  */
 gpg_error_t
 ks_hkp_mark_host (ctrl_t ctrl, const char *name, int alive)
 {
@@ -974,6 +973,10 @@ ks_hkp_search (ctrl_t ctrl, parsed_uri_t uri, const char *pattern,
   if (err)
     goto leave;
 
+  err = dirmngr_status (ctrl, "SOURCE", hostport, NULL);
+  if (err)
+    goto leave;
+
   /* Peek at the response.  */
   {
     int c = es_getc (fp);
@@ -1082,6 +1085,10 @@ ks_hkp_get (ctrl_t ctrl, parsed_uri_t uri, const char *keyspec, estream_t *r_fp)
   if (err)
     goto leave;
 
+  err = dirmngr_status (ctrl, "SOURCE", hostport, NULL);
+  if (err)
+    goto leave;
+
   /* Return the read stream and close the HTTP context.  */
   *r_fp = fp;
   fp = NULL;