Convert locks that protect name hash, ID hash and typelist from mutex(9) to rwlock(9) based locks.
Convert locks that protect name hash, ID hash and typelist from
mutex(9) to rwlock(9) based locks.

While here remove dropping lock when processing NGM_LISTNODES,
and NGM_LISTTYPES generic commands. We don't need to drop it
since memory allocation is done with M_NOWAIT.

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