ubifs: Set double hash cookie also for RENAME_EXCHANGE

We developed RENAME_EXCHANGE and UBIFS_FLG_DOUBLE_HASH more or less in
parallel and this case was forgotten. :-(

Cc: [e-mail]
Fixes: d63d61c16972 ("ubifs: Implement UBIFS_FLG_DOUBLE_HASH")
Signed-off-by: Richard Weinberger <[e-mail]>

fs/ubifs/journal.c

···
 	dent1->nlen = cpu_to_le16(fname_len(snd_nm));
 	memcpy(dent1->name, fname_name(snd_nm), fname_len(snd_nm));
 	dent1->name[fname_len(snd_nm)] = '\0';
+	set_dent_cookie(c, dent1);
 	zero_dent_node_unused(dent1);
 	ubifs_prep_grp_node(c, dent1, dlen1, 0);
 
···
 	dent2->nlen = cpu_to_le16(fname_len(fst_nm));
 	memcpy(dent2->name, fname_name(fst_nm), fname_len(fst_nm));
 	dent2->name[fname_len(fst_nm)] = '\0';
+	set_dent_cookie(c, dent2);
 	zero_dent_node_unused(dent2);
 	ubifs_prep_grp_node(c, dent2, dlen2, 0);