Split test case in ironic.tests.conductor.test_manager
Split test case in ironic.tests.conductor.test_manager

Currently ManagerTestCase is really huge and is quite hard to
navigate in. This patch creates one more common mix-in for
setUp and splits this test case into several smaller.

Also fixes usage of mock in setUp.

Change-Id: Ib1b69723fe595dfd4d8c7f118b91a59eda7001a6

NaohiroTamura/ironic,NaohiroTamura/ironic,debayanray/ironic_backup,hpproliant/ironic,naototty/vagrant-lxc-ironic,bacaldwell/ironic,ionutbalutoiu/ironic,pshchelo/ironic,openstack/ironic,froyobin/ironic,dims/ironic,SauloAislan/ironic,Tan0/ironic,devananda/ironic,redhat-openstack/ironic,rdo-management/ironic,supermari0/ironic,naototty/vagrant-lxc-ironic,SauloAislan/ironic,Tehsmash/ironic,ionutbalutoiu/ironic,rackerlabs/ironic,bacaldwell/ironic,ramineni/myironic,pshchelo/ironic,dims/ironic,faizan-barmawer/openstack_ironic,openstack/ironic,naterh/ironic