Corrected data generator fixture with posts_meta fields

refs https://github.com/TryGhost/Ghost/pull/11102

- When splitting out posts_meta table out of posts table, the fixtures were not corrected.
- There were no acceptance/regression tests which involved posts_meta fields which is why the error was not detected

test/unit/services/rss/generate-feed_spec.js

@@ -23,6 +23,7 @@ describe('RSS: Generate Feed', function () {
         _.each(posts, function (post) {
             post.url = '/' + post.slug + '/';
             post.primary_author = {name: 'Joe Bloggs'};
+            post.meta_description = post.posts_meta && post.posts_meta.meta_description;
         });
     });
 

test/utils/fixtures/data-generator.js

@@ -49,10 +49,12 @@ DataGenerator.Content = {
             html: '<!--kg-card-begin: markdown--><h2 id=\"testing\">testing</h2>\n<p>mctesters</p>\n<ul>\n<li>test</li>\n<li>line</li>\n<li>items</li>\n</ul>\n<!--kg-card-end: markdown-->',
             plaintext: 'testing\nmctesters\n\n * test\n * line\n * items',
             feature_image: 'http://placekitten.com/500/200',
-            meta_description: 'test stuff',
             published_at: new Date('2015-01-03'),
             featured: true,
-            uuid: '2ac6b4f6-e1f3-406c-9247-c94a0496d39d'
+            uuid: '2ac6b4f6-e1f3-406c-9247-c94a0496d39d',
+            posts_meta: {
+                meta_description: 'test stuff'
+            }
         },
         {
             id: ObjectId.generate(),