Bug 2038: check reply_body_max_size before ICAP

Bug 2038: check reply_body_max_size before ICAP

Use newly added HttpReply::expectedBodyTooLarge() check to support the
reply_body_max_size ACL when the expected body size may be known. The check
is now shared between server and client sides.

The server side needs to do the checks before feeding the data to ICAP.
Otherwise, ICAP service may suck a large response in and spit a small response
out. It was decided that the reply_body_max_size ACL should apply to the
virgin response as well.

The server side does not perform HttpReply::receivedBodyTooLarge() check yet.