Remove unused rooms before trying to create

Prevent the strange situation where trying to create tells you the room already exists, and when you try to join, the error is that the room doesn't exist

public/vroom.pl

@@ -243,6 +243,7 @@ post '/create' => sub {
     $self->stash(msg => $self->l('ERROR_NAME_INVALID'));
     return $self->render('error');
   }
+  $self->delete_rooms;
   if ($self->create_room($name,$self->session('name'))){
     $self->redirect_to('/'.$name);
   }