Updated openstack/openstack
Project: openstack/ceilometer  58490558eee9238050dd0989af9e709daaa05c6a
null
storage: factorize not implemented methods

There's a lot of driver that are not implementing everything, and as
time goes by, this is getting and going to be more and more common. Not
all drivers are suited to do everything, so implementing every methods
as abstract makes a lot of NotImplementedError raising redundant.

This patch makes stop using that and remove a lot of useless copy pasted
code.

Change-Id: I9e48c4f0484033061a3c3461d761e4cea4b8e75e