test-visitor-serialization: Pass &error_abort to qobject_from_json()

qmp_deserialize() calls qobject_from_json() ignoring errors.  It
passes the result to qobject_input_visitor_new(), which asserts it's
not null.  Therefore, we can just as well pass &error_abort to
qobject_from_json().
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NKevin Wolf <kwolf@redhat.com>
Message-Id: <1488317230-26248-16-git-send-email-armbru@redhat.com>

tests/test-visitor-serialization.c

@@ -1037,7 +1037,7 @@ static void qmp_deserialize(void **native_out, void *datap,
     visit_complete(d->qov, &d->obj);
     obj_orig = d->obj;
     output_json = qobject_to_json(obj_orig);
-    obj = qobject_from_json(qstring_get_str(output_json), NULL);
+    obj = qobject_from_json(qstring_get_str(output_json), &error_abort);
 
     QDECREF(output_json);
     d->qiv = qobject_input_visitor_new(obj);