Close outgoing ws if incoming ws emits error

Fixes http-party#559, which contains a full reproduction recipe.

Author: glasser

lib/http-proxy/passes/ws-incoming.js

@@ -88,10 +88,16 @@ var passes = exports;
       common.setupOutgoing(options.ssl || {}, options, req)
     );
     // Error Handler
-    proxyReq.on('error', onError);
+    proxyReq.on('error', onOutgoingError);
 
     proxyReq.on('upgrade', function(proxyRes, proxySocket, proxyHead) {
-      proxySocket.on('error', onError);
+      proxySocket.on('error', onOutgoingError);
+      // The pipe below will end proxySocket if socket closes cleanly, but not
+      // if it errors (eg, vanishes from the net and starts returning
+      // EHOSTUNREACH). We need to do that explicitly.
+      socket.on('error', function () {
+        proxySocket.end();
+      });
 
       common.setupSocket(proxySocket);
 
@@ -106,7 +112,7 @@ var passes = exports;
 
     return proxyReq.end(); // XXX: CHECK IF THIS IS THIS CORRECT
 
-    function onError(err) {
+    function onOutgoingError(err) {
       if (clb) {
         clb(err, req, socket);
       } else {