Properly free resources when destroying the TCP hostcache while tearing down a network stack (in the VIMAGE jail+vnet case).
Properly free resources when destroying the TCP hostcache while
tearing down a network stack (in the VIMAGE jail+vnet case).

For that break out the logic from tcp_hc_purge() into an internal
function we can call from both, the sysctl handler and the
tcp_hc_destroy().

Sponsored by:	ISPsystem
Reviewed by:	silby, lstewart
MFC After:	8 days

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