This patch adds a few optimizations when using the amphora driver.
1. It increases the amp_active_retries from 10 to 30. This increases
the time we wait for nova to mark an instance "ACTIVE". The old default
of 10 was one minute forty seconds, but in some clouds it's been observed
that the nova schedule can get overloaded and take longer than a minute
forty to schedule the instance. Setting this to 30 means we will wait
five minutes for nova to schedule the instance.
2. It enables TCP kernel splicing in HAProxy. This has been shown to
reduce the CPU overhead for very high rate TCP load balancers.
3. Finally it enables "safe" HTTP keepalives on the backend member
connections [1]. This increases the request rate possible while using HTTP
protocol listeners and members.
[1] http://cbonte.github.io/haproxy-dconv/1.6/configuration.html#4-http-reuse
Change-Id: I3af009cac9a9edc8aef793b52c6a1488fde2c59b
53772f5320