gpg: Fix regression in option "self-sigs-only".

* g10/import.c (read_block): Make sure KEYID is availabale also on a
pending packet.

• Reported-by: Phil Pennock
• Fixes-commit: 2e349bb6173789e0e9e42c32873d89c7bc36cea4
• Signed-off-by: Werner Koch <wk@gnupg.org>