sheepdog: fix resource leak with sd_snapshot_create

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>

block/sheepdog.c

@@ -2341,6 +2341,7 @@ static int sd_snapshot_create(BlockDriverState *bs, QEMUSnapshotInfo *sn_info)
     if (ret < 0) {
         error_report("failed to create inode for snapshot: %s",
                      error_get_pretty(local_err));
+        error_free(local_err);
         goto cleanup;
     }