Bug 22110: Fix editing of adjustments for CurrencyFormat != US

Bug 22110: Fix editing of adjustments for CurrencyFormat != US

When using CurrencyFormat FR or CH the editing an amount behave
badly. Example: changing displayed 1,00 to 1,11 would save as 1,00.

At the moment Koha only understands decimal dot, not comma.
So every time data is entered, we use decimal dot.

1) Add an adjustment to an invoice
2) Change system preference CurrencyFormat to FR or CH
3) Verify the amount displays with a decimal comma
4) Try changing the amount to something like 1,11
5) Save the amount
6) Verify it shows 1.00
7) Apply patch
8) Refresh the invoice page if necessary
9) Verify amount is now shown as 1.00
10) Repeat test, use 1.11
11) Verify it will be stored correctly.

Signed-off-by: Mackey Johnstone <mackeyfj@gmail.com>
Signed-off-by: mikael <mikael.Olangcay-Brisebois@inlibro.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>