Changed log_querydone to accept response parameter.

Changed routine `log_querydone' to receive `response' array as
parameter. It is used to log response code and number of resource
records in the answer section of the response message. Added a new
static array to hold text explanation for numeric response codes.

Updated dnscache.c to pass response array to `log_querydone'. Also
updated log.h header to change prototype for `log_querydone'.