Ignore ebusy when deleting a directory

Reported in https://github.com/rabbitmq/rabbitmq-server/discussions/11047

This error manifests when the quorum directory is its own mount point

(cherry picked from commit 84a5172)

Author: lukebakken

deps/rabbit/src/rabbit_file.erl

@@ -244,6 +244,7 @@ recursive_delete1(Path) ->
         false -> case prim_file:delete(Path) of
                      ok              -> ok;
                      {error, enoent} -> ok; %% Path doesn't exist anyway
+                     {error, ebusy}  -> ok; %% Ignore (rabbitmq/rabbitmq-server#11047)
                      {error, Err}    -> {error, {Path, Err}}
                  end;
         true  -> case prim_file:list_dir(Path) of