More memory cleanups

Signed-off-by: Mario Danic <mario@lovelyhq.com>

app/src/main/java/com/nextcloud/talk/controllers/CallNotificationController.java

@@ -297,7 +297,6 @@ public class CallNotificationController extends BaseController {
 
         if (handler == null) {
             handler = new Handler();
-
             ncApi = ApplicationWideApiHolder.getInstance().getNcApiInstanceForAccountId(userBeingCalled.getId(), null);
         }
 

app/src/main/java/com/nextcloud/talk/controllers/ChatController.java

@@ -469,6 +469,7 @@ public class ChatController extends BaseController implements MessagesListAdapte
     @Override
     public void onDestroy() {
         super.onDestroy();
+        adapter = null;
         inChat = false;
         ApplicationWideCurrentRoomHolder.getInstance().clear();
         leaveRoom();