added Client constructor back on pool to enable instrumentation (brianc#998)

Author: martinkuba

lib/pool.js

@@ -6,6 +6,7 @@ var genericPool = require('generic-pool');
 
 module.exports = function(Client) {
  var pools = {
+ Client: Client,
  //dictionary of all key:pool pairs
  all: {},
  //reference to the client constructor - can override in tests or for require('pg').native
@@ -23,7 +24,7 @@ module.exports = function(Client) {
  reapIntervalMillis: clientConfig.reapIntervalMillis || defaults.reapIntervalMillis,
  log: clientConfig.poolLog || defaults.poolLog,
  create: function(cb) {
- var client = new Client(clientConfig);
+ var client = new pools.Client(clientConfig);
  // Ignore errors on pooled clients until they are connected.
  client.on('error', Function.prototype);
  client.connect(function(err) {