Correct failing integration test.

Author: Twipped

test/integration/connection/test-named-paceholders.js

@@ -56,7 +56,7 @@ assert.equal(sql, 'SELECT * from test_table where num1 < 2 and num2 > 100');
 connection.end();
 
 var pool = common.createPool();
-pool.config.namedPlaceholders = true;
+pool.config.connectionConfig.namedPlaceholders = true;
 pool.query('SELECT :a + :a as sum', {a: 2}, function (err, rows, fields) {
   pool.end();
   if (err) {