minor fix in CancelVirtualTransaction

When Who What
2019-02-03 10:26:21 Andres Freund (andresfreund) Closed in commitfest 2019-01 with status: Returned with feedback
2019-01-17 07:38:23 Peter Eisentraut (petere) New status: Waiting on Author
2019-01-04 10:55:46 Peter Eisentraut (petere) Added petere as reviewer
2019-01-04 10:32:51 Pavan Deolasee (pavan) Added pavan as reviewer
2018-12-06 20:38:38 Álvaro Herrera (alvherre) Changed authors to Álvaro Herrera (alvherre)
2018-12-06 20:38:30 Álvaro Herrera (alvherre) Attached mail thread 20180629170512.d6kof6l6uu3qqpd6@alvherre.pgsql
2018-12-06 20:38:30 Álvaro Herrera (alvherre) Created patch record