The Elasticsearch endpoints in use by logstash are currently hardcoded
to localhost in both the logstash monitoring config and the default
logstash pipeline template. This commit allows this to be configured,
such that (multiple) remote endpoints can be specified for the case that
logstash is not co-located with elasticsearch. The default behaviour is
unchanged.
Change-Id: Id871f201168ff882a5b37677747c3484f908298f
b21034c4b8