qapi: fix examples of blockdev-add with qcow2
The examples use "qcow2" driver with the wrong member name for
BlockdevRef alternate type. This patch changes all wrong member names
from "file" to "data-file" which is the correct member name in
BlockdevOptionsQcow2 for the BlockdevRef field.
Problem was noticed when using the example as a test case for Go
bindings.
Signed-off-by: Victor Toso <victortoso@redhat.com>
Message-Id: <
20220901085840.22520-9-victortoso@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>