auto retrieve keys from PKA. Thsi allows to specify an email address

so that gpg can get the key from DNS.  This helps with opportunistic
encryption.  No integration with the trust modell yet.

g10/gpgv.c

@@ -280,6 +280,18 @@ keyserver_import_keyid( u32 *keyid, void *dummy )
     return -1;
 }
 
+/* Stub:
+ * Because we only work with trusted keys, it does not make sense to
+ * get them from a keyserver
+ */
+int
+keyserver_import_fprint (const byte *fprint, size_t fprint_len,
+                         struct keyserver_spec *keyserver)
+{
+    return -1;
+}
+
+
 /* Stub:
  * No encryption here but mainproc links to these functions.
  */