gpg: Mark disabled keys and add show-ownertrust list option.
* g10/options.h (LIST_SHOW_OWNERTRUST): New. * g10/keylist.c (print_key_line): Show wonertrust and always show whether a key is disabled. * g10/gpg.c (parse_list_options): Add "show-ownertrust". * g10/gpgv.c (get_ownertrust_string): Add stub. * g10/test-stubs.c (get_ownertrust_string): Add stub.
Note that in a --with-colons listing the ownertrust has always been
emitted and the disabled state is marked in that listing with a
special 'D' usage.