opr: install afs/opr.h and opr/lock.h

opr: install afs/opr.h and opr/lock.h

These headers are (transitively) referenced from rx_pthread.h, which is pulled
in from rx.h when AFS_PTHREAD_ENV is defined.  As such, we are presenting an
incomplete public API without this header.

Reviewed-on: https://gerrit.openafs.org/13054
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Anders Kaseorg <andersk@mit.edu>
Tested-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Michael Meffie <mmeffie@sinenomine.net>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>
(cherry picked from commit 792dd44ac57032a3f2a4743c83c8a0208a08ecec)

Change-Id: I9785e4d408b2838a2c65ae372717a6c92e38767b
Reviewed-on: https://gerrit.openafs.org/13141
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Benjamin Kaduk <kaduk@mit.edu>