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)
Make sure that hypervisor nodename is set correctly in FakeDriver

This resolves an issue where the wrong host name is used when
executing some sample_api tests individually.

Resolves bug 1177802.

Change-Id: I29af026e29ff8c70bb6b4c81f1bdf28cdea11140
(cherry picked from commit 8b79ac24a83854de9f57bb3526a2edbd0b6d64d2)
Merge "Make nova.virt.fake.FakeDriver useable in integration testing" into stable/grizzly
Merge "Make sure that hypervisor nodename is set correctly in FakeDriver" into stable/grizzly