apache.conf.in: include input byte count if available
If mod_logio is not available all we can display is the output byte
count in the log.
But if mod_logio is available we can also display the input byte count
and both will include all bytes.
To avoid changing the number of fields we combine them with '->' so that
if say the request was 155 bytes and the response was 213 bytes the log
entry would have '155->213' for the size field when mod_logio is enabled
and just 213 (less the headers size) when it's not.
Signed-off-by: Kyle J. McKay <mackyle@gmail.com>