Fix description submission in form handling

When we submitted an image the description would remain empty. THis was
because of some weird typo in form handling. Get an attribute with
.get('description') and not with .get(['description']). With this patch,
descriptions actually go into the database.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

mediagoblin/submit/views.py

@@ -42,7 +42,7 @@ def submit_start(request):
             # create entry and save in database
             entry = request.db.MediaEntry()
             entry['title'] = request.POST['title']
-            entry['description'] = request.POST.get(['description'])
+            entry['description'] = request.POST.get('description')
             entry['media_type'] = u'image' # heh
             entry['uploader'] = request.user