Revert "Linaro London: use new bigger flavour"
Revert "Linaro London: use new bigger flavour"

linaro-london got new Ceph setup so we can go back to 8vcpu per node.

This reverts commit 1900f336f732eb021719ffd68131d607dc0052bf.

Change-Id: I2e70dd03600e5168eb47d7d2fff2f1c364f0f301

openstack-infra/project-config,openstack-infra/project-config