Removing unused custom graph id fixes axes tests

Let's see about the other tests

Author: nicholas-esterer

test/jasmine/assets/create_graph_div.js

@@ -1,9 +1,8 @@
 'use strict';
 
-module.exports = function createGraphDiv(id) {
-    id = (id === undefined) ? 'graph' : id;
+module.exports = function createGraphDiv() {
     var gd = document.createElement('div');
-    gd.id = id;
+    gd.id = 'graph';
     document.body.appendChild(gd);
 
     // force the graph to be at position 0,0 no matter what

test/jasmine/assets/destroy_graph_div.js

@@ -1,8 +1,7 @@
 'use strict';
 
-module.exports = function destroyGraphDiv(id) {
-    id = (id === undefined) ? 'graph' : id;
-    var gd = document.getElementById(id);
+module.exports = function destroyGraphDiv() {
+    var gd = document.getElementById('graph');
 
     if(gd) document.body.removeChild(gd);
 };