SUNRPC: Ensure that rpc_mkpipe returns a refcounted dentry

If not, we cannot guarantee that idmap->idmap_dentry, gss_auth->dentry and
clnt->cl_dentry are valid dentries.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/idmap.c

@@ -132,6 +132,8 @@ nfs_idmap_delete(struct nfs4_client *clp)
 
 	if (!idmap)
 		return;
+	dput(idmap->idmap_dentry);
+	idmap->idmap_dentry = NULL;
 	rpc_unlink(idmap->idmap_path);
 	clp->cl_idmap = NULL;
 	kfree(idmap);