The example return type has the wrong member name. Fix it.

Problem was noticed when using the example as a test case for Go
bindings.

Signed-off-by: Victor Toso <victortoso@redhat.com>
---
 qapi/machine.json | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/qapi/machine.json b/qapi/machine.json
index 4782eea2c3..abb2f48808 100644
--- a/qapi/machine.json
+++ b/qapi/machine.json
@@ -958,9 +958,9 @@
 #
 # -> { "execute": "query-hotpluggable-cpus" }
 # <- {"return": [
-#      { "props": { "core": 8 }, "type": "POWER8-spapr-cpu-core",
+#      { "props": { "core-id": 8 }, "type": "POWER8-spapr-cpu-core",
 #        "vcpus-count": 1 },
-#      { "props": { "core": 0 }, "type": "POWER8-spapr-cpu-core",
+#      { "props": { "core-id": 0 }, "type": "POWER8-spapr-cpu-core",
 #        "vcpus-count": 1, "qom-path": "/machine/unattached/device[0]"}
 #    ]}'
 #
-- 
2.37.2