btrfs-progs: restore: fix off-by-one len check

Fix a check of len versus PATH_MAX in function copy_symlink(), to
account for the terminating null byte.

Resolves-Coverity-CID: 1296749
Signed-off-by: Vincent Stehlé <vincent.stehle@freescale.com>
Signed-off-by: David Sterba <dsterba@suse.com>

cmds-restore.c

@@ -863,7 +863,7 @@ static int copy_symlink(struct btrfs_root *root, struct btrfs_key *key,
 
 	len = btrfs_file_extent_inline_item_len(leaf,
 			btrfs_item_nr(path->slots[0]));
-	if (len > PATH_MAX) {
+	if (len >= PATH_MAX) {
 		fprintf(stderr, "Symlink '%s' target length %d is longer than PATH_MAX\n",
 				fs_name, len);
 		ret = -1;