vfs: don't BUG_ON() if following a /proc fd pseudo-symlink results in a symlink

It's "normal" - it can happen if the file descriptor you followed was
opened with O_NOFOLLOW.

Reported-by: Dave Jones <davej@redhat.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/namei.c

diff --git a/fs/namei.c b/fs/namei.c
index 961bc12..57ae9c8 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -689,8 +689,6 @@
 	nd->path = *path;
 	nd->inode = nd->path.dentry->d_inode;
 	nd->flags |= LOOKUP_JUMPED;
-
-	BUG_ON(nd->inode->i_op->follow_link);
 }
 
 static inline void put_link(struct nameidata *nd, struct path *link, void *cookie)