afs: Include FID in DoLockWarning

Provide the FID that is being locked when we warn about byte-range
locks, so the user can find what file the process is trying to lock.

Change-Id: I56a185c200ac73045ee29b79410e27222c2637f2
Reviewed-on: http://gerrit.openafs.org/10795
Reviewed-by: D Brashear <shadow@your-file-system.com>
Tested-by: D Brashear <shadow@your-file-system.com>