A GETATTR request can race with FUSE_NOTIFY_INVAL_INODE, resulting in the
attribute cache being updated with stale information after the
invalidation.

Fix this by bumping the attribute version in fuse_reverse_inval_inode().
Reported-by: NKrzysztof Rusek <rusek@9livesdata.com>
Signed-off-by: NMiklos Szeredi <mszeredi@redhat.com>