responde time of the http publish

Change-Id: Ib9e677dba5ce74227671da468bc6dbd50c0e5c52
Merge branch 'ganglia' of https://github.com/scroiset/ceilometer into ganglia

Conflicts:
	ceilometer/publisher/http.py

Change-Id: Iff9ec55b3cd42211c7c682f93c8c6123e8968835