Merge branch 'briar-recycler-view-log' into 'master'

Stop periodic list update only once

When testing the forum unread code, I noticed the recycler view is detaching twice. Once because the stop method is called and once because the view detaches from the window. Wouldn't it be safe to null the refresher when the updates are stopped?

See merge request !478

briar-android/src/main/java/org/briarproject/briar/android/view/BriarRecyclerView.java

@@ -208,6 +208,7 @@ public class BriarRecyclerView extends FrameLayout {
 		if (refresher != null) {
 			LOG.info("Removing Handler Callback");
 			handler.removeCallbacks(refresher);
+			refresher = null;
 		}
 	}