- change dns_qpdata_t to qpcnode_t (QP cache node), and dns_qpdb_t to qpcache_t, as these types are only accessed locally. - also change qpdata_t in qpzone.c to qpznode_t (QP zone node), for consistency. - make the refcount declarations for qpcnode_t and qpznode_t static, using the new ISC_REFCOUNT_STATIC macros.