BUG/MINOR: stream-int: also update analysers timeouts on activity

BUG/MINOR: stream-int: also update analysers timeouts on activity

Between 1.6 and 1.7, some parts of the stream forwarding process were
moved into lower layers and the stream-interface had to keep the
stream's task up to date regarding the timeouts. The analyser timeouts
were not updated there as it was believed this was not needed during
forwarding, but actually there is a case for this which is "option
contstats" which periodically triggers the analyser timeout, and this
change broke the option in case of sustained traffic (if there is some
I/O activity during the same millisecond as the timeout expires, then
the update will be missed).

This patch simply brings back the analyser expiration updates from
process_stream() to stream_int_notify().

It may be backported as far as 1.7, taking care to adjust the fields
names if needed.