MINOR: filters: Review and simplify errors handling

MINOR: filters: Review and simplify errors handling

First, it is useless to abort the both channel explicitly. For HTTP streams,
http_reply_and_close() is called. This function already take care to abort
processing. For TCP streams, we can rely on stream_retnclose().

To set termination flags, we can also rely on http_set_term_flags() for HTTP
streams and sess_set_term_flags() for TCP streams. Thus no reason to handle
them by hand.

At the end, the error handling after filters evaluation is now quite simple.