TableStructureSpec: use right var

The other tests create a TableStructure
object and then calls loadFromJson on
that object, so do the same in the last
test.

test/Map/TableStructureSpec.js

@@ -443,7 +443,7 @@ describe("TableStructure", function () {
       }
     };
     var tableStructureNoAddr = new TableStructure("foo", optionsNoAddr);
-    tableStructureNoAddr = tableStructure.loadFromJson(dataNoAddr);
+    tableStructureNoAddr = tableStructureNoAddr.loadFromJson(dataNoAddr);
     expect(tableStructureNoAddr.hasAddress).toBe(false);
   });