gpg: Make import filter data object more flexible.
* g10/main.h (import_filter_t): New. * g10/import.c (struct import_filter_s): Declare struct. (import_keep_uid, import_drop_sig): Replace by ... (import_filter): new. Adjust all users. (cleanup_import_globals): Move code to ... (release_import_filter): new. (save_and_clear_import_filter): New. (restore_import_filter): New.
- Signed-off-by: Werner Koch <wk@gnupg.org>