Immediately remove delivery receipts from the retry cache (#1719)

js/background.js

@@ -708,7 +708,7 @@
             source: deliveryReceipt.source
         });
 
-        receipt.on('remove', ev.confirm);
+        ev.confirm();
 
         // Calling this directly so we can wait for completion
         return Whisper.DeliveryReceipts.onReceipt(receipt);

js/delivery_receipts.js

@@ -67,7 +67,6 @@
                         receipt.get('source'),
                         receipt.get('timestamp')
                     );
-                    resolve();
                 }
             }.bind(this)).catch(function(error) {
                 console.log(