qom-qmp-cmds: fix two memleaks in qmp_object_add

'type/id' forgot to free in qmp_object_add, this patch fix that.

The leak stack:
Direct leak of 84 byte(s) in 6 object(s) allocated from:
    #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
    #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
    #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
    #3 0x56344954e692 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:258
    #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
    qemu#5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
    qemu#6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
    qemu#7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
    qemu#8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136

Direct leak of 54 byte(s) in 6 object(s) allocated from:
    #0 0x7fe2a5ebf768 in __interceptor_malloc (/lib64/libasan.so.5+0xef768)
    #1 0x7fe2a5044445 in g_malloc (/lib64/libglib-2.0.so.0+0x52445)
    #2 0x7fe2a505dd92 in g_strdup (/lib64/libglib-2.0.so.0+0x6bd92)
    #3 0x56344954e6c4 in qmp_object_add /mnt/sdb/qemu-new/qemu_test/qemu/qom/qom-qmp-cmds.c:267
    #4 0x563449960f5a in do_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:132
    qemu#5 0x563449960f5a in qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/qapi/qmp-dispatch.c:175
    qemu#6 0x563449498a30 in monitor_qmp_dispatch /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:145
    qemu#7 0x56344949a64f in monitor_qmp_bh_dispatcher /mnt/sdb/qemu-new/qemu_test/qemu/monitor/qmp.c:234
    qemu#8 0x563449a92a3a in aio_bh_call /mnt/sdb/qemu-new/qemu_test/qemu/util/async.c:136

Fixes: 5f07c4d
Reported-by: Euler Robot <euler.robot@huawei.com>
Signed-off-by: Pan Nengyuan <pannengyuan@huawei.com>
Message-Id: <20200310064640.5059-1-pannengyuan@huawei.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Acked-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

qom/qom-qmp-cmds.c

@@ -247,26 +247,22 @@ void qmp_object_add(QDict *qdict, QObject **ret_data, Error **errp)
     QDict *pdict;
     Visitor *v;
     Object *obj;
-    const char *type;
-    const char *id;
+    g_autofree char *type = NULL;
+    g_autofree char *id = NULL;
 
-    type = qdict_get_try_str(qdict, "qom-type");
+    type = g_strdup(qdict_get_try_str(qdict, "qom-type"));
     if (!type) {
         error_setg(errp, QERR_MISSING_PARAMETER, "qom-type");
         return;
-    } else {
-        type = g_strdup(type);
-        qdict_del(qdict, "qom-type");
     }
+    qdict_del(qdict, "qom-type");
 
-    id = qdict_get_try_str(qdict, "id");
+    id = g_strdup(qdict_get_try_str(qdict, "id"));
     if (!id) {
         error_setg(errp, QERR_MISSING_PARAMETER, "id");
         return;
-    } else {
-        id = g_strdup(id);
-        qdict_del(qdict, "id");
     }
+    qdict_del(qdict, "id");
 
     props = qdict_get(qdict, "props");
     if (props) {