Add support for running multiple n-cpus for performance testing

When using the fake VIRT_DRIVER, we can launch an arbitrary number of
instances, the next step for performance testing is running an arbitrary
number of n-cpus. This can be done with the following settings in your localrc

 VIRT_DRIVER=fake
 NUMBER_FAKE_NOVA_COMPUTE=50

This can be used for things like measuring load from n-cpu's periodic tasks.

Change-Id: I40e0f05374e2c10c48ea6b8816ef6e7609b3dc80
Merge "Add support for running multiple n-cpus for performance testing"
Update projects to global requirements before setup

We've agreed that we should be using global requirements, so
force projects to be updated to global requirements before we
test them.

Co-Authored-With: Monty Taylor <mordred@inaugust.com>

Change-Id: I0652f639673e600fd7508a9869ec85f8d5ce4518