use the correct pg bindings

Author: Christophe Macabiau

test/integration/client/cancel-query-tests.js

@@ -1,5 +1,4 @@
 var helper = require(__dirname+"/test-helper");
-var pg = require(__dirname + '/../../../lib');
 
 //before running this test make sure you run the script create-test-tables
 test("cancellation of a query", function() {
@@ -29,9 +28,9 @@ test("cancellation of a query", function() {
 		rows4++;
 	});
 
-	pg.cancel(helper.connectionString, client, query1);
-	pg.cancel(helper.connectionString, client, query2);
-	pg.cancel(helper.connectionString, client, query4);
+	helper.pg.cancel(helper.connectionString, client, query1);
+	helper.pg.cancel(helper.connectionString, client, query2);
+	helper.pg.cancel(helper.connectionString, client, query4);
 
 	setTimeout(function() {
 		assert.equal(rows1, 0);