gnucash maint: [lot-viewer] don't show Open & Close dates when not applicable

[Christopher Lam]

Updated	 via  https://github.com/Gnucash/gnucash/commit/f3b3ccb8 (commit)
	from  https://github.com/Gnucash/gnucash/commit/0d0ab002 (commit)



commit f3b3ccb8d891eeb4571b3036a2e5ea96c33d5137
Author: Christopher Lam <christopher.lck at gmail.com>
Date:   Mon Aug 29 10:50:51 2022 +0800

    [lot-viewer] don't show Open & Close dates when not applicable
    
    Bug: an empty lot would show "Opened" date as 01/01/1970.
    
    Fix on lot editor UI:
    Empty lots have opening date "Empty", blank closing date.
    Open lots have appropriate opening date, closing date "Open"
    Closed lots have appropriate opening and closing dates.



Summary of changes:
 gnucash/gnome/dialog-lot-viewer.c | 70 +++++++++++++++++++++++++++++++--------
 1 file changed, 57 insertions(+), 13 deletions(-)