I missed this tweak in the undo of a prior xattr optimization.
Added a flag to disable xattr hlink optimization.

I added a compatibility flag for protocol 31 that will let both sides
know if they should be using the xattr optimization that attempted to
avoid sending xattr info for hardlinked files.  Since this optimization
was causing some issues, this compatibility flag will ensure that both
sides know if they should be trying to use the optimization or not.