Updated openstack/openstack
Project: openstack/ceilometer  9b695e87619b44d880d239ac3d0058ea36a7205f

Improve a bit performance of Ceilometer

we shouldn't use <array>.extend([<generator>]) it's similiar to
<array>.extend(<generator>) but slower

Change-Id: Ic859e9a477f03b680e1ac0db1498261a3dc24997