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: I449d0822a39554a1f45b5b509d70e093e7ceb690
Reviewed-on: http://gerrit.openafs.org/3171
Reviewed-by: Derrick Brashear <shadow@dementia.org>
Tested-by: Derrick Brashear <shadow@dementia.org>