Remove MissingComputeNodeTestCase for res tracker
Remove MissingComputeNodeTestCase for res tracker

The MissingComputeNodeTestCase "unit test" in test_resource_tracker.py
wasn't testing anything that TestInitComputeNode in test_tracker.py
wasn't already testing. MissingComputeNodeTestCase was inheriting from
TestCase instead of NoDBTestCase, making it slower to run and not
testing the actual isolated surface area that TestInitComputeNode was
testing. So, goodbye MissingComputeNodeTestCase.

Change-Id: I87bcbbbec3f7a8ae04dc56b00dc9db530d1ca1bd

rahulunair/nova,Juniper/nova,rajalokan/nova,bigswitch/nova,vmturbo/nova,Juniper/nova,hanlind/nova,klmitch/nova,hanlind/nova,rajalokan/nova,alaski/nova,mahak/nova,Juniper/nova,jianghuaw/nova,phenoxim/nova,bigswitch/nova,vmturbo/nova,rajalokan/nova,mikalstill/nova,mikalstill/nova,sebrandon1/nova,gooddata/openstack-nova,jianghuaw/nova,sebrandon1/nova,jianghuaw/nova,vmturbo/nova,hanlind/nova,rahulunair/nova,vmturbo/nova,gooddata/openstack-nova,openstack/nova,openstack/nova,sebrandon1/nova,cloudbase/nova,klmitch/nova,rahulunair/nova,mikalstill/nova,klmitch/nova,klmitch/nova,cloudbase/nova,mahak/nova,Juniper/nova,mahak/nova,gooddata/openstack-nova,rajalokan/nova,cloudbase/nova,openstack/nova,alaski/nova,gooddata/openstack-nova,jianghuaw/nova,phenoxim/nova