redis: switch incoming to use list
redis: switch incoming to use list

redis provides data structures, we shouldn't creat a new key for
every single 'measure object'. this patch stores all incoming
measures in a list under a key associated with metric.

Change-Id: Idfb5026fa90148c8f15b401893de196baea1f92c

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