Add Core, Ram and Disk filter to fake virt setting

The FakeVirt driver shouldn't need custom scheduling options, so it run
instead of a real virt driver for testing purposes. This simplifies the
use case where someone wants to run the FakeVirt driver along side a
real driver so someone can test there cloud application without wasting
real instances.

Since the FakeVirt driver should look like it has near infinite resources,
turn on Core, Ram and Disk filters to make sure the drive works with them
enabled.

Change-Id: Ic7ec87e4d497d9db58eec93f2b304fe9770a2bbc
Related-Bug: #1268943
Install MySQL-python for keystone with rpm system

MySQL-python is needed for keystone and we were installing it
implicitely only for apts and not for rpms. Fix keystone only devstack
install on a pristine vm.

Change-Id: I0d117513af4e2ad58635f7a7b22f7a6e3ff36a38
Configurable Keystone admin workers

The API_WORKERS option wasn't setting the number of admin workers
for the Keystone server when running in eventlet mode. This will
allow for control of throughput and memory usage.

Change-Id: Iecbce4a601f93784164e53d8b0c542d48f7b5650
Merge "Configurable Keystone admin workers"
Merge "Install MySQL-python for keystone with rpm system"
Merge "Add Core, Ram and Disk filter to fake virt setting"
Merge branch 'master' of https://github.com/openstack-dev/devstack