* history.c: Some cleanup.

(expand_modules): Removed this stub function.
(get_history_log_name): Don't return const since it is freshly
allocated.
(history_write): Add version number to history records.  Use tag
fields like other record types.
(fill_hrec): Load version number & postprocess history records as
needed.  Zero records with memset.
(read_hrecs_file): Don't zero records redundantly with fill_hrec().
(report_hrecs): Find tag data in the same place as other record types.
* sanity.sh (basic2-64): Expect new tag records.
* tag.c: Some cleanup.
(cvstag): Move history log call to...
(tag_filesdoneproc): ...here, where we have more information.