When OpenStack API services are behind Apache2, HTTP Keep-Alive timeout
is 5 seconds out of the box. Polling operations with the same interval
as HTTP Keep-Alive timeout can cause intermittent failures like:
Unable to establish connection to
https://nova.example.com:8774/v2.1/servers/UUID:
('Connection aborted.', RemoteDisconnected('Remote end closed connection
without response',))
Let's avoid the same value by default as Apache2's HTTP Keep-Alive
timeout.
Closes-Bug: #1946912
Change-Id: Ibda414b129a44d38ed3c3a4b5a43fd45e63ec122