Make nova.virt.fake.FakeDriver useable in integration testing

With this change nova.virt.fake.FakeDriver can be used for scale testing
using devstack. By setting 'compute_driver = nova.virt.fake.FakeDriver'
in nova.conf and disabiling quota and other limits, we can load up nova
to think it is running 1000's of instances.  This particular scenario is
analagous to how the baremetal driver will work (one machine managing
100's to 1000's of instances).

Make nova.virt.fake.FakeDriver use CONF.host for hostname.

Change-Id: I731ca2968176b4e39dd2fe7fc99f479cc568398b
(cherry picked from commit 03a2463be8034ee4764ac97e8020fc3d3a32f1fd)
disable quotas
Disable RamFilter