It may happen that pfsync holds the last reference on a state. In this case keys had already been freed. If encountering such state, then just release last reference.
It may happen that pfsync holds the last reference on a state. In this
case keys had already been freed. If encountering such state, then
just release last reference.

Not sure this can happen as a runtime race, but can be reproduced by
the following scenario:

- enable pfsync
- disable pfsync
- wait some time
- enable pfsync

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