Cleans up power_off and power_on semantics

compute.api changes:
  * improves state handling for delete/restrore
  * removes hack to deal with SHUTOFF on start
  * fixes api tests (volume shouldn't detach on stop)

compute.manager changes:
  * uses power_off/power_on for stop/start

virt.libvirt changes:
  * implements power_off/power_on for libvirt
  * synchronizes usage of domain.create()
  * cleans up usage of instance.name
  * added tests for power_on and power_off
  * fixes bug 1006950

Change-Id: I91845a643e3f97955e7c81ca57c6ee5aa0a3d295

nova/tests/test_virt_drivers.py

@@ -176,6 +176,22 @@ class _VirtDriverTestCase(test.TestCase):
             self.ctxt, instance_ref, 'dest_host', instance_type_ref,
             network_info)
 
+    @catch_notimplementederror
+    def test_power_off(self):
+        instance_ref, network_info = self._get_running_instance()
+        self.connection.power_off(instance_ref)
+
+    @catch_notimplementederror
+    def test_test_power_on_running(self):
+        instance_ref, network_info = self._get_running_instance()
+        self.connection.power_on(instance_ref)
+
+    @catch_notimplementederror
+    def test_test_power_on_powered_off(self):
+        instance_ref, network_info = self._get_running_instance()
+        self.connection.power_off(instance_ref)
+        self.connection.power_on(instance_ref)
+
     @catch_notimplementederror
     def test_pause(self):
         instance_ref, network_info = self._get_running_instance()