Removed redundant check during tip migration

gratipay/models/team.py

@@ -158,19 +158,6 @@ def to_dict(self):
         }
 
     def migrate_tips(self):
-        payment_instructions = self.db.all("""
-            SELECT pi.*
-              FROM payment_instructions pi
-              JOIN teams t ON t.slug = pi.team
-              JOIN participants p ON t.owner = p.username
-             WHERE p.username = %s
-               AND pi.ctime < t.ctime
-        """, (self.owner, ))
-
-        # Make sure the migration hasn't been done already
-        if payment_instructions:
-            raise AlreadyMigrated
-
         return self.db.one("""
         WITH rows AS (