Aborted network requests should use protocol's "Failed" status (#215)

This patch starts using "Failed" command for request interception instead of
"Aborted".

The "Aborted" status also has a side-effect of cancelling the navigation, so
there will be no error on the page and form puppeteer's standpoint, the navigation
will never complete.

lib/NetworkManager.js

@@ -243,7 +243,7 @@ class InterceptedRequest {
     this._handled = true;
     this._client.send('Network.continueInterceptedRequest', {
       interceptionId: this._interceptionId,
-      errorReason: 'Aborted'
+      errorReason: 'Failed'
     });
   }