[haproxy] Active Sessions panel should not be using rate()

[szook]

in the haproxy-2-full.json file on the "Active Sessions" panel, the haproxy_frontend_current_sessions and haproxy_backend_current_sessions metrics are "gauge" metrics rather than "counter", so applying the rate() function obfuscates the data.

I suggest changing these to something like:

sum(haproxy_frontend_current_sessions{proxy=~"$frontend",instance="$host"}) by (instance)

[rfrail3]

You are right, thanks for it Szook.