- Update gnucash-libdbi-0.9.patch: fix usage of internal function
_gnucash-libdbi-0.9.patch (boo#898974).

- Update to version 2.6.4:
+ Add business lot scrubbing to Check & Repair->All/This
transaction(s).
+ Add context to generic translatable string.
+ Add scrub function to reduce the amount of lot links used.
+ Add some date format checking and make sure generated dates are
the correct user selected format, not always locale format.
+ Allow the ability to skip rows when importing transactions.
+ Always use the price we display to calculate the current value
of an account.
+ Better period totals formatting in Invoices.
+ CSV Export: factor out function to generate regular expression.
+ CSV Import transform macro into function.
+ Convert ISO-8859-1 account chart templates to UTF-8.
+ Correct txf output to use a minus sign, rather than
parenthesis.
+ Fix document type dispay for credit notes on owner report.
+ Fix test-backend-dbi segfault with libdbi-0.9.0.
+ Handle the case of scrubbing a lot link between two
non-document lots.
+ Lots of refactoring.
+ Chart-of-Account Templates Updated.
+ Bugs fixed: bgo#120199, bgo#434462, bgo#509263, bgo#610202,
bgo#630638, bgo#671615, bgo#688965, bgo#692249, bgo#695240,
bgo#707243, bgo#711440, bgo#711567, bgo#719457, bgo#719457,
bgo#720427, bgo#720934, bgo#722140, bgo#722200, bgo#723145,
bgo#723442, bgo#725054, bgo#725366, bgo#726449, bgo#726888,