Change #ifdef INVARIANTS panic into KASSERT, and print some useful information to diagnose the issue, in handle_complete_freeblocks().
Change #ifdef INVARIANTS panic into KASSERT, and print some useful
information to diagnose the issue, in handle_complete_freeblocks().

Reviewed by:	jeff
Tested by:	pho

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase