No capitalize step

lib/cartodb/api/query_tables_api.js

@@ -1,6 +1,6 @@
 var sqlApi = require('../sql/sql_api');
 var PSQL = require('cartodb-psql');
-var Step = require('step');
+var step = require('step');
 
 function QueryTablesApi(pgConnection, metadataBackend) {
     this.pgConnection = pgConnection;
@@ -78,7 +78,7 @@ QueryTablesApi.prototype.runQuery = function(username, query, queryHandler, call
 
         var params = {};
 
-        Step(
+        step(
             function setAuth() {
                 self.pgConnection.setDBAuth(username, params, this);
             },
@@ -109,7 +109,7 @@ QueryTablesApi.prototype.runQuery = function(username, query, queryHandler, call
 
     } else {
 
-        Step(
+        step(
             function getApiKey() {
                 self.metadataBackend.getUserMapKey(username, this);
             },