Fix index issue with records in HostDBRecord::select_best_srv

[cmcfarlen]

This came up in a copilot review of a fix unrelated to this issue so I created this separate PR to address this.

It seems the loop structure at some point looped over an index, but was changed to a range based loop, neglecting to change one aspect. But it was not noticed because the index variable is declared before the loop.

The issue is the is_down is always checked on the first target, so could skip up targets or use down targets depending.

[Copilot]

Pull request overview

Fixes a subtle selection bug in HostDBRecord::select_best_srv where a stale index variable from a prior index-based loop was still being used after converting the loop to range-based iteration, potentially causing incorrect skipping of SRV targets.

Changes:

• Remove the unused / stale loop index variable and stop indexing rr[i] inside the range-based loop.
• Use the range-loop reference (target) consistently for is_down() checks.
• Re-scope the i index to the weighted-selection loop where it is actually needed.

[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated no new comments.

[masaori335]

Looks good.