[PATCH] netrc: 'default' with no credentials is not a match

[PATCH] netrc: 'default' with no credentials is not a match

Test 486 verifies.

Reported-by: Yihang Zhou
Closes #15908

Backported by: Dr. Tobias Quathamer <toddy@debian.org>

Changes:
* Refresh patch context for lib/netrc.c
* Use tests/data/Makefile.inc to add new test instead of
  tests/data/Makefile.am, because that has only been
  introduced in later versions of curl.
* Replace "%LOGDIR" with "log" due to its absence in bookworm.

Gbp-Pq: Name CVE-2025-0167.patch