BUG/MINOR: filters: Always set FLT_END analyser when CF_FLT_ANALYZE flag is set

BUG/MINOR: filters: Always set FLT_END analyser when CF_FLT_ANALYZE flag is set

CF_FLT_ANALYZE flags may be set before the FLT_END analyser. Thus if an error is
triggered in the mean time, this may block the stream and prevent it to be
released. It is indeed a problem only for the response channel because the
response analysers may be skipped on early errors.

So, to prevent any issue, depending on the code path, the FLT_END analyser is
systematically set when the CF_FLT_ANALYZE flag is set.

This patch must be backported in all stable branches.