4039 zfs_rename()/zfs_link() needs stronger test for XDEV
Reviewed by: Gordon Ross <gordon.ross@nexenta.com>
Reviewed by: Kevin Crowe <kevin.crowe@nexenta.com>
Reviewed by: Saso Kiselkov <skiselkov.ml@gmail.com>
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Dan McDonald <danmcd@nexenta.com>