reduce machine number from Linaro London
reduce machine number from Linaro London

Use Linaro US instead

Change-Id: I194b5847963cb5af7bf9655e7922251c07c0e6bf
Signed-off-by: Kevin Zhao <9fc648be98fc18cb4028b7c8c8516da572477616@linaro.org>

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