Fix KA header not checking strategy (#7483)
Fix KA header not checking strategy (#7483)

Fixes handle_request_keep_alive_headers directly checking the old
parentage for parent_is_proxy, instead of the abstract func which
checks the strategy if it exists.

This would cause the Connection header to get added instead of the
correct Proxy-Connection when Strategies are used.
pbchou/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,duke8253/trafficserver,pbchou/trafficserver,duke8253/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,pbchou/trafficserver,vmamidi/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,pbchou/trafficserver,pbchou/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,bryancall/trafficserver,duke8253/trafficserver,bryancall/trafficserver