Neither the VNC or SPICE code for password changes provides error reporting at source, leading the callers to report a largely useless generic error message. Fixing this removes one of the two remaining needs for the undesirable error_printf_unless_qmp() method. While fixing this the error message hint is improved to recommend the 'password-secret' option which allows securely passing a password at startup. Reported-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>