down with assert, up with osi_Assert

down with assert, up with osi_Assert

because NDEBUG breaks things which happen inside an assert,
be done with that. instead, call osi_Assert wherever possible.
doesn't work for code which builds before rx; those cases we handle
by ensuring no operations happen inside the assert(). side effect:
move all pthread operations wrapped in asserts to MUTEX_mumble and
CV_mumble calls where those exist, so the assertions happen all in
one set of macroes.

Change-Id: I9fd8a0fdfdaed5ed55de3e5c0c4673d4714e7441
Reviewed-on: http://gerrit.openafs.org/3001
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Reviewed-by: Jeffrey Altman <jaltman@openafs.org>
Tested-by: Derrick Brashear <shadow@dementia.org>