Read receipts: Log sender and timestamp when related msg not found

FREEBIE

js/background.js

@@ -338,7 +338,7 @@
         var read_at   = ev.timestamp;
         var timestamp = ev.read.timestamp;
         var sender    = ev.read.sender;
-        console.log('read receipt ', sender, timestamp);
+        console.log('read receipt', sender, timestamp);
         var receipt = Whisper.ReadReceipts.add({
             sender    : sender,
             timestamp : timestamp,

js/read_receipts.js

@@ -32,7 +32,10 @@
                         this.remove(receipt);
                     }.bind(this));
                 } else {
-                    console.log('No message for read receipt');
+                    console.log(
+                        'No message for read receipt',
+                        receipt.get('sender'), receipt.get('timestamp')
+                    );
                 }
             }.bind(this));
         },