fuse: rcu-delay freeing fuse_conn

makes ->permission() and ->d_revalidate() safety in RCU mode independent
from vfsmount_lock.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

diff --cc fs/fuse/cuse.c
Simple merge

diff --cc fs/fuse/fuse_i.h
Simple merge

diff --cc fs/fuse/inode.c
Simple merge