BUG/MEDIUM: http-ana: Clear request analyzers when applying redirect rule

BUG/MEDIUM: http-ana: Clear request analyzers when applying redirect rule

A bug was introduced by the commit 2d5650082 ("BUG/MEDIUM: http-ana: Reset
channels analysers when returning an error").

The request analyzers must be cleared when a redirect rule is applied. It is
not a problem if the redirect rule is inside an http-request ruleset because
the analyzer takes care to clear it. However, when it comes from a redirect
ruleset (via the "redirect ..."  directive), because of the above commit,
the request analyzers are no longer cleared. It means some HTTP request
analyzers may be called while the request channel was already flushed. It is
totally unexpected and may lead to crash.

Thanks to Yves Lafon for reporting the problem.

This patch must be backported everywhere the above commit was backported.