Revert "CA-109035: Remove the correct xenstore key when PCI unplugging."

This reverts commit 1fd7e5aad5a2f272cc0ed0b39f5a1969bfb3e9f4.

Removing this patch for the tech preview since it hasn't been QA'd yet.

Signed-off-by: John Else <john.else@citrix.com>