suzerain: #2979 use new maybe_{a,b,c} hooks

Attempts to use NRBC-ready operator accumulate and assembly
routines as what was in place was demonstrably wrong.

git-svn-id: https://svn.ices.utexas.edu/repos/pecos/suzerain/trunk@44001 0bd85f0b-c151-43b9-a1e9-27231104551f