message: [FIX] Fix synchronization of removed subscriptions
  When a subscription is removed from the server via another client, when the
  mobile app is relaunched the subscriptions were not being removed properly.
  Changed the logic to use the subscriptionResult.remove array from the server
  and the _id property to fix.
diff: @@ -51,9 +51,9 @@ const handleRoomsRequest = function* handleRoomsRequest({ params }) {
  const subCollection = db.get('subscriptions');
  const messagesCollection = db.get('messages');
  - const subsIds = subscriptions.map(sub => sub.rid).concat(roomsResult.remove.map(room => room._id));
  + const subsIds = subscriptions.map(sub => sub._id).concat(subscriptionsResult.remove.map(sub => sub._id));
  if (subsIds.length) {
  - const existingSubs = yield subCollection.query(Q.where('id', Q.oneOf(subsIds))).fetch();
  + const existingSubs = yield subCollection.query(Q.where('_id', Q.oneOf(subsIds))).fetch();
  const subsToUpdate = existingSubs.filter(i1 => subscriptions.find(i2 => i1._id === i2._id));
  const subsToCreate = subscriptions.filter(i1 => !existingSubs.find(i2 => i1._id === i2._id));
  const subsToDelete = existingSubs.filter(i1 => !subscriptions.find(i2 => i1._id === i2._id));
  