Redo r166423. It is important not only skip freeing multicast entires when underlying interface is detached, but also purge pointers to them, to avoid double-free in future.
Redo r166423. It is important not only skip freeing multicast
entires when underlying interface is detached, but also purge
pointers to them, to avoid double-free in future.

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