Add Proxy-Connection to list of hop-by-hop headers stripped by HTTP proxy

psiphon/httpProxy.go

@@ -147,6 +147,7 @@ func (proxy *HttpProxy) ServeHTTP(responseWriter http.ResponseWriter, request *h
 	}
 }
 
+// From // https://golang.org/src/pkg/net/http/httputil/reverseproxy.go:
 // Hop-by-hop headers. These are removed when sent to the backend.
 // http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
 var hopHeaders = []string{
@@ -154,7 +155,8 @@ var hopHeaders = []string{
 	"Keep-Alive",
 	"Proxy-Authenticate",
 	"Proxy-Authorization",
-	"Te", // canonicalized version of "TE"
+	"Proxy-Connection", // see: http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/web-proxy-connection-header.html
+	"Te",               // canonicalized version of "TE"
 	"Trailers",
 	"Transfer-Encoding",
 	"Upgrade",