BUG/MINOR: mux-h2: Also expect data when waiting for a tunnel establishment

When a client H2 stream is waiting for a tunnel establishment, it must state
it expects data from server. It is the second fix that should fix
regressions of the commit 2722c04b ("MEDIUM: mux-h2: Don't expect data from
server as long as request is unfinished")

It is a 2.8-specific bug. No backport needed.
1 file changed