Fix accessing a destroyed gnc_commodity.

[Christian Stimming]

Log Message:
-----------
Fix accessing a destroyed gnc_commodity.

2005-10-16  Christian Stimming  <stimming at tuhh.de>

	* src/backend/file/io-gncxml-v2.c: Fix accessing a gnc_commodity
	after it has been destroyed - xaccTransSetCurrency requires the
	original currency still to exist.

Tags:
----
gnucash-gnome2-dev

Modified Files:
--------------
    gnucash:
        ChangeLog
    gnucash/src/backend/file:
        io-example-account.c
        io-gncxml-v2.c