bug4438/MT5496 budget Exceeds total allocation

bug4438/MT5496 budget Exceeds total allocation

This is a followup :
When editing a budget, the check for the total allocation would take into account the budget itself.
Showing an improper error message
The problem was solved when adding a child budget but not when editing the same budget.

Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Signed-off-by: Chris Cormack <chrisc@catalyst.net.nz>
(cherry picked from commit 3e297c6cb8e7b6b73b9df2e2ae1ba3dd0bc014e7)

Signed-off-by: Chris Nighswonger <chris.nighswonger@gmail.com>