statsd: tweak logging
statsd: tweak logging

This logs only "resource already exist" on debug, so it sounds less
warny for operators.
Log something when the daemon is started and ready to process.

Change-Id: Ia67c7679fa46d8f0c2fb48aed9fd4132a992733a

sileht/gnocchi,gnocchixyz/gnocchi,sileht/gnocchi,leandroreox/gnocchi,gnocchixyz/gnocchi,leandroreox/gnocchi