Move set above rewrite to fix uninitialized variable

[AlexFenlon]

Proposed changes

Moved set default_connection_header above rewrites to fix a warning in the logs about that variable being uninitialized.

I did extensive testing before making this change to make sure this won't affect anyone. Using my own web socket app and the examples/custom-resources/traffic-splitting/cafe-virtual-server.yaml in the issue to test what changes are made if I moved this set before the rewrites.

Doing a websocket connecton via npx wscat -c ws://cafe.example.com:80 does not give a warning which means it's only curl giving the warning

Curl hasn't recognised websockets due to curl being designed for standard http only and therefore gives the warning as http_upgrade is blank doing a curl and not using websockets as websockets automatically sets the upgrade and connection headers. That is why there is a warning.

Doing the websocket connection defines the http_upgrade which then maps the default_connection_header so therefore it is defined and initialised so it doesn't give the warning.

This curl command doesn't give a warning before and after moving the set so therefore everything will work as normal, this change will just mask the warning
curl --include \ --header "Connection: Upgrade" \ --header "Upgrade: websocket" \ http://cafe.example.com:80/

Resolves: #5082

Checklist

Before creating a PR, run through this checklist and mark each as complete.

• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
• I have rebased my branch onto main
• I will ensure my PR is targeting the main branch and pulling from my branch from my own fork

[pdabelf5]

👍

[jjngx]

🚀