swift/sysctl: do not disable net.ipv4.tcp_timestamps

Turn timestamps off to reduce performance spikes related to timestamp
generation. The sysctl command controls the values of TCP related
entries, setting the timestamps kernel parameter found at
/proc/sys/net/ipv4/tcp_timestamps.

It should be enabled in order to make Swift & Ceph working correctly.

Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>
loadbalancer: Use binding class but keep listen_https compat

Remove the use of the listen_https class but remain compatible
with previous use of listen_https