In ipo_tdb the flow contains a reference counted TDB cache. This

In ipo_tdb the flow contains a reference counted TDB cache.  This
may prevent that tdb_free() is called.  It is not a real leak as
ipsecctl -F or termination of iked flush this cache when they remove
the IPsec policy.  Move the code from tdb_free() to tdb_delete(),
then the kernel does the cleanup itself.
OK mvs@ tobhe@