MEDIUM: http-ana: Do nothing in wait-for-request analyzer if not htx

MEDIUM: http-ana: Do nothing in wait-for-request analyzer if not htx

If http_wait_for_request() analyzer is called with a non-htx stream, nothing
is performed and we return immediatly. For now, it is totally unexpected.
But it will be true during TCP to H1 upgrades, once fixed. Indeed, there
will be a transition period during these upgrades. First the mux will be
upgraded and the not the stream, and finally the stream will be upgraded by
the mux once ready. In the meantime, the stream will still be in raw
mode. Nothing will be performed in wait-for-request analyzer because it will
be the mux responsibility to handle errors.

This patch is required to fix the TCP to H1 upgrades.