BUG/MINOR: quic: Wrong RTT computation (srtt and rrt_var)

Due to the fact that several variable values (rtt_var, srtt) were stored as multiple
of their real values, some calculations were less accurate as expected.

Stop storing 4*rtt_var values, and 8*srtt values.
Adjust all the impacted statements.

Must be backported as far as 2.6.

(cherry picked from commit fb4294be55d372a20aee0c0f430c508a20bfb020)
|cf: some changes were applied in quic_conn.c because quic_cli.c and
     quic_trace.c don't exist]
Signed-off-by: Christopher Faulet <cfaulet@haproxy.com>
4 files changed