test: minimize test-http-get-pipeline-problem

Reduce resoures required by test.

Clarify comment explaining source of test and what the test is looking
for.

Fixes: nodejs#5725

test/parallel/test-http-get-pipeline-problem.js

@@ -1,19 +1,21 @@
 'use strict';
-// We are demonstrating a problem with http.get when queueing up many
-// transfers. The server simply introduces some delay and sends a file.
-// Note this is demonstrated with connection: close.
+// In previous versions of Node.js (e.g., 0.6.0), this sort of thing would halt
+// after http.globalAgent.maxSockets number of files.
+// See https://groups.google.com/forum/#!topic/nodejs-dev/V5fB69hFa9o
 var common = require('../common');
 var assert = require('assert');
 var http = require('http');
 var fs = require('fs');
 
+http.globalAgent.maxSockets = 1;
+
 common.refreshTmpDir();
 
 var image = fs.readFileSync(common.fixturesDir + '/person.jpg');
 
 console.log('image.length = ' + image.length);
 
-var total = 100;
+var total = 10;
 var requests = 0, responses = 0;
 
 var server = http.Server(function(req, res) {