Fix duplicated column definition

This is why copy pasting code is bad, but I've no idea how exactly
I can abstract out the ContentProvider related stuff

Change-Id: Ib668ad8cd2302b832afc69b97951f3a6b1dcfe5b

commons/src/main/java/org/wikimedia/commons/campaigns/Campaign.java

@@ -157,7 +157,6 @@ public class Campaign {
                 COLUMN_ENABLED,
                 COLUMN_TITLE,
                 COLUMN_DESCRIPTION,
-                COLUMN_DESCRIPTION,
                 COLUMN_TRACKING_CATEGORY,
                 COLUMN_BODY
         };