qobject: Catch another straggler for use of qdict_put_str()

Patch created mechanically by rerunning:

  $  spatch --sp-file scripts/coccinelle/qobject.cocci \
            --macro-file scripts/cocci-macro-file.h \
            --dir . --in-place
Signed-off-by: NPhilippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: NMarkus Armbruster <armbru@redhat.com>
Acked-by: NMichael S. Tsirkin <mst@redhat.com>
Message-Id: <20180705155811.20366-2-f4bug@amsat.org>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

qobject/block-qdict.c

@@ -577,7 +577,7 @@ static QObject *qdict_crumple_for_keyval_qiv(QDict *src, Error **errp)
         if (!tmp) {
             tmp = qdict_clone_shallow(src);
         }
-        qdict_put(tmp, ent->key, qstring_from_str(s));
+        qdict_put_str(tmp, ent->key, s);
         g_free(buf);
     }