We used to attempt to remove any port specification before recording
HTTP host headers in logs. Doing so would (1) remove potentially useful
information, (2) not match what the documentation seemed to suggest, and
(3) fail for IP6 addresses containing colons.
We now record the original HOST header as is.
Addresses #1844.
The body-lengths of sub-entities, like multipart messages, got counted
twice by mistake: once upon the end of the sub-entity and then again
upon the end of the top-level entity that contains all sub-entities.
The size of just the top-level entity is the correct one to use.
