Description of the Pull Request (PR):

In updateSystem(), Webclient.Get() returns an HTTP response, but never calls resp.Body.Close(). When using --once option, the process exits quickly after the HTTP request, but the underlying TCP connection may not be properly closed. This leaves the local port in a TIME_WAIT state, causing subsequent runs to fail with "address already in use."

In addition, connections in the pool were not being properly cleaned up on exit, and the connection was not told it was ok to re-use a recently-used port.

This fixes or addresses the following GitHub issues:

• Fixes: wwclient sometimes reports "address already in use" when secure=true #2009

Reviewer checklist

The reviewer checks the following items before merging the PR.

• The PR is based on the appropriate branch (typically main)
• All commits are "Signed off" (e.g., using git commit --signoff) in agreement to the DCO
• The CHANGELOG has been updated, if necessary, and under the correct release heading
• The userdocs have been updated, if necessary
• The submitter is listed in the contributors file
• The test suite has been updated, if necessary