* agent/findkey.c (write_extended_private_key): Add args serialno and
keyref. Write a Token line if that does not yet exist.
(agent_write_private_key): Add args serialno and keyref and change all
callers.
(agent_write_shadow_key): Skip leading spaces.
* agent/keyformat.txt: Improve extended key format docs.
--
Noet that the extended key forma is the defaqult in 2.3. This patch
is a first step to better handle tokens which carray the same key.
Signed-off-by: Werner Koch <wk@gnupg.org>