Clean up assertion

Clean up assertion

The AFS code has multiple different assertion implementations in
userspace. This patchset is the start of bringing some sanity to them.

In rx, we have osi_Assert, a user/kernel assertion macro. This is only
available to libraries which have RX dependencies

In util, we redefine the standard 'assert()' macro to provide a
cross-platform assertion solution.

Because util has an RX dependency, neither of these provide an
assertion solution for libraries which should be independent of rx.
So, pull the assertion code out of util, and put it into opr, as a new
opr_Assert() macro. Implement the userspace osi_Assert in terms of this
macro, leaving the kernel variant untouched.

Update callers to the new macro and header file names.

Change-Id: I780b30ec1ea1207daa17127df4d5fbf9a94481b6
Reviewed-on: http://gerrit.openafs.org/5394
Reviewed-by: Derrick Brashear <shadow@dementix.org>
Tested-by: BuildBot <buildbot@rampaginggeek.com>