afs: remove lock dead code

afs: remove lock dead code

Since OpenAFS 1.0, LockWait has been commented out, and the following
routines have been unreferenced:
- ObtainLock
- ReleaseLock
- afs_osi_SleepR
- afs_osi_SleepW
- afs_osi_SleepS

Remove them from the code and comments.

No functional change is incurred by this commit.

Change-Id: I480d023282878243f9a92f432d7bbec7028af70c
Reviewed-on: https://gerrit.openafs.org/14407
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Cheyenne Wills <cwills@sinenomine.net>
Reviewed-by: Andrew Deason <adeason@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>