Stop signed key rotation as export process starts

js/background.js

@@ -101,6 +101,8 @@
     };
 
     Whisper.events.on('start-shutdown', function() {
+      Whisper.RotateSignedPreKeyListener.stop();
+
       if (messageReceiver) {
         messageReceiver.close().then(function() {
           messageReceiver = null;

js/rotate_signed_prekey_listener.js

@@ -59,6 +59,15 @@
                     setTimeoutForNextRun();
                 }
             });
+        },
+        stop: function() {
+            console.log('Stopping signed prekey rotation');
+            clearTimeout(timeout);
+            timeout = null;
+        },
+        start: function() {
+            console.log('Starting signed prekey rotation');
+            setTimeoutForNextRun();
         }
     };
 }());