[InterNetNews/inn] a3d0d5: rnews: Fix segfault when logging duplicates

[Julien ÉLIE]

  Branch: refs/heads/main
  Home:   https://github.com/InterNetNews/inn
  Commit: a3d0d506037674ec57dcb418b114c63f1cade8b3
      https://github.com/InterNetNews/inn/commit/a3d0d506037674ec57dcb418b114c63f1cade8b3
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2022-05-24 (Tue, 24 May 2022)

  Changed paths:
    M frontends/rnews.c

  Log Message:
  -----------
  rnews: Fix segfault when logging duplicates

GCC 12.1 warned about the use of a freed pointer.
The segfault occurs when running "rnews -d" and a duplicate article is
provided (probably a rare use case).