Don't loop over nonetype

fix #5124

couchpotato/core/plugins/dashboard.py

@@ -96,7 +96,7 @@ class Dashboard(Plugin):
                         if late:
                             media['releases'] = fireEvent('release.for_media', media['_id'], single = True)
 
-                            for release in media.get('releases'):
+                            for release in media.get('releases', []):
                                 if release.get('status') in ['snatched', 'available', 'seeding', 'downloaded']:
                                     add = False
                                     break