vfs: remove unused i_op->rename

No in-tree uses remain.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/namei.c b/fs/namei.c
index adb0414..02803bd 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -4369,12 +4369,9 @@
 	if (error)
 		return error;
 
-	if (!old_dir->i_op->rename && !old_dir->i_op->rename2)
+	if (!old_dir->i_op->rename2)
 		return -EPERM;
 
-	if (flags && !old_dir->i_op->rename2)
-		return -EINVAL;
-
 	/*
 	 * If we are going to change the parent - check write permissions,
 	 * we'll need to flip '..'.
@@ -4428,14 +4425,8 @@
 		if (error)
 			goto out;
 	}
-	if (!old_dir->i_op->rename2) {
-		error = old_dir->i_op->rename(old_dir, old_dentry,
-					      new_dir, new_dentry);
-	} else {
-		WARN_ON(old_dir->i_op->rename != NULL);
-		error = old_dir->i_op->rename2(old_dir, old_dentry,
-					       new_dir, new_dentry, flags);
-	}
+	error = old_dir->i_op->rename2(old_dir, old_dentry,
+				       new_dir, new_dentry, flags);
 	if (error)
 		goto out;