gnucash maint: [budget-flow] delay creating exchange-fn until a valid budget exists

[Christopher Lam]

Updated	 via  https://github.com/Gnucash/gnucash/commit/f771513f (commit)
	from  https://github.com/Gnucash/gnucash/commit/ca6604c9 (commit)



commit f771513f4ff9c77705a1d9217893963342082950
Author: Christopher Lam <christopher.lck at gmail.com>
Date:   Sat Dec 4 11:43:19 2021 +0800

    [budget-flow] delay creating exchange-fn until a valid budget exists
    
    because it needs budget period end-date.



Summary of changes:
 gnucash/report/reports/standard/budget-flow.scm | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)