Removed default useragent header in ParseUrl http.GET

[coolcoolnoworries]

ParseUrl uses http.get to pull the PAC, without defining headers. This sends a default "Go-http-client/1.1" header along with every request. The user agent header is unnecessary and in some cases creates logging issues. Add code to use client object instead and explicitly set user agent header to empty so that it does not get sent with every PAC request.