Fixed a minor bug that crashed the app

app/src/main/java/de/kuschku/quasseldroid_ng/ui/chat/drawer/BufferViewConfigAdapter.java

@@ -227,6 +227,9 @@ public class BufferViewConfigAdapter extends ExpandableRecyclerAdapter<NetworkVi
     }
 
     public void selectConfig(int id) {
+        if (context.client() == null || context.client().bufferViewManager() == null)
+            return;
+
         QBufferViewConfig newconfig = context.client().bufferViewManager().bufferViewConfig(id);
         Parcelable state = (newconfig == config) ? saveState() : null;