Use the right predicate in ->atomic_open() instances

->atomic_open() can be given an in-lookup dentry *or* a negative one
found in dcache.  Use d_in_lookup() to tell one from another, rather
than d_unhashed().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index f4645c5..e2e7c74 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -853,7 +853,7 @@
 	struct p9_fid *fid, *inode_fid;
 	struct dentry *res = NULL;
 
-	if (d_unhashed(dentry)) {
+	if (d_in_lookup(dentry)) {
 		res = v9fs_vfs_lookup(dir, dentry, 0);
 		if (IS_ERR(res))
 			return PTR_ERR(res);