Crash bug when updating reports

[joslwah]

Change 18426 "Bug #121695: Support account reparenting through drag and drop
in the account tree view" introduces a crash bug when updating reports.
Reverting this change stops the crashes.

To crash gnucash open a report, for example "Net worth barchart" and then
change by removing one account.  Click apply or ok and gnucash crashes
reliably.

I've tested reverting that patch against current head.  Seems to work fine,
but I've really only tested updating a report.

If it is relevant, this is on an Ubuntu 9.10 machine, running 32bit (x86).