Convert logstash ES output to HTTP.

The logstash elasticsearch output seems to degrade over time and slow
down. Restarting the logstash daemon temporarily corrects this problem.
Switch to the elasticsearch HTTP output to see if that corrects the
problem as well.

Note the logstash watchdog is disabled by this change as logstash
daemons using elasticsearch HTTP output will not join the elasticsearch
cluster which will force the watchdog to always trip. To avoid this
issue disable the watchdog.

Change-Id: I77044b26fa10fb1fc3690a0464d79d55bed2fe00