[InterNetNews/inn] 4b2c71: Fix double free in tdx-util

[Russ Allbery]

  Branch: refs/heads/2.6
  Home:   https://github.com/InterNetNews/inn
  Commit: 4b2c71d2842b8b1b410c0911ee7139b5c23c7244
      https://github.com/InterNetNews/inn/commit/4b2c71d2842b8b1b410c0911ee7139b5c23c7244
  Author: Russ Allbery <eagle at eyrie.org>
  Date:   2021-09-13 (Mon, 13 Sep 2021)

  Changed paths:
    M storage/tradindexed/tdx-util.c

  Log Message:
  -----------
  Fix double free in tdx-util

The data structure is designed to be cached with a reference count,
and therefore is freed when a search is closed if it hasn't been
added to a cache.  tdx-util was unaware of that and was freeing it
again explicitly, causing a double free and a test failure (but no
security implications, since it happened immediately before process
exit).  Remove the duplicate free.

Add some cleanup to an early return path in the same function.