Fix an infinite loop in ReportAccount::calculateAccountHierarchy caused by an invalid budget that was obtained by deleting a category and assigning it to another category which was not budgeted. In that case MyMoneyBudget::account will return the empty account group for the new category when calling 'MyMoneyBudget::AccountGroup toBudget = b.account(categoryId);' thus if you add toBudget with toBudget.id() instead of toBodget with categoryId then an account group with an empty id is created.
Backported to the stable branch.