Comment 2 for bug 1503276

The root cause is in the difference of how rpc listeners are started.
core plugin (ml2) doesn't start rpc listeners in __init__ method, unlike l3_router plugin.

So for l3 queues we have rpc_workers+1 listener (+1 goes from parent process).
For cases when rpc_workers > 0, q-plugin is only consumed from rpc_workers, but not from the parent process.

This doesn't indicate any malfunction and we don't need to fix it.