[fedora-virt] F21 virt test day rescheduled to September 11th

[Cole Robinson]

To avoid two back to back test days, we've moved the Fedora 21 virt test day
one day forward to September 11th. Landing page is now here:

https://fedoraproject.org/wiki/Test_Day:2014-09-11_Virtualization

Thanks,
Cole