audit: incorrect ref counting in audit tree tag_chunk

tag_chunk has bad exit paths in which the inotify ref counting is wrong.
At the top of the function we found &old_watch using  inotify_find_watch().
inotify_find_watch takes a reference to the watch.  This is never dropped
on an error path.
Signed-off-by: Eric Paris <eparis@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/audit_tree.c

@@ -385,6 +385,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 	mutex_lock(&inode->inotify_mutex);
 	if (inotify_clone_watch(&old->watch, &chunk->watch) < 0) {
 		mutex_unlock(&inode->inotify_mutex);
+		put_inotify_watch(&old->watch);
 		free_chunk(chunk);
 		return -ENOSPC;
 	}
@@ -394,6 +395,7 @@ static int tag_chunk(struct inode *inode, struct audit_tree *tree)
 		chunk->dead = 1;
 		inotify_evict_watch(&chunk->watch);
 		mutex_unlock(&inode->inotify_mutex);
+		put_inotify_watch(&old->watch);
 		put_inotify_watch(&chunk->watch);
 		return 0;
 	}