* Change hc_remove() to return a -errno if an error occurs instead of -1.

* Change hc_remove() to return a -errno if an error occurs instead of -1.

* Adjust most hc_remove() calls to xremove(), which calls hc_remove() and
  retries with a chflags/remove sequence if the initial removal fails with
  EPERM.  This should help when there are hardlinks to a file marked schg.