BUG/MINOR: http-ana: Disable fast-fwd for unfinished req waiting for upgrade

BUG/MINOR: http-ana: Disable fast-fwd for unfinished req waiting for upgrade

If a request is waiting for a protocol upgrade but it is not finished, the
data fast-forwarding is disabled. Otherwise, the request analyzers will miss
the end of the message.

This case is possible since the commit 01fb1a54 ("BUG/MEDIUM: mux-h1/mux-h2:
Reject upgrades with payload on H2 side only"). Indeed, before, a protocol
upgrade was not allowed for request with payload. But it is now possible and
this comes with a side-effect. It is not really satisfying but for now there
is no other way to sync the muxes and the applicative stream. It seems to be
a reasonnable fix for now, waiting for a deeper refactoring.

This patch must be backported with the commit above.