T5489: Add sysctl TCP congestion control by default to BBR
Add by default sysctl TCP congestion control to BBR.
Default value cubic is not optimal.
net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr
(cherry picked from commit b99ed37dd1cff3310437ff8ccf1a27cd20714c41)