kbx: Call skipfnc callback to filter out keys
* kbx/keybox-search.c (blob_get_keyid): New. (keybox-search): Call skipfnc callback function.
This patch (tentatively) fixes
The keybox_search function in kbx/keybox-search.c currently ignores
the skipfnc callback, but the validate_key_list function in
g10/trustdb.c uses such a callback to exclude ultimately trusted keys.
- GnuPG-bug-id: T1794