Add Hyper-V driver in the "compute_driver" option description

The description of the option "compute_driver" should include
hyperv.HyperVDriver along with the other supported driver.

Change-Id: Ic7e16fd5154609987b2ef0b6f8ee52619ccf489c
Closes-bug: #1347777

nova/virt/driver.py

@@ -33,9 +33,9 @@ from nova.virt import event as virtevent
 driver_opts = [
     cfg.StrOpt('compute_driver',
                help='Driver to use for controlling virtualization. Options '
-                   'include: libvirt.LibvirtDriver, xenapi.XenAPIDriver, '
-                   'fake.FakeDriver, baremetal.BareMetalDriver, '
-                   'vmwareapi.VMwareVCDriver'),
+                    'include: libvirt.LibvirtDriver, xenapi.XenAPIDriver, '
+                    'fake.FakeDriver, baremetal.BareMetalDriver, '
+                    'vmwareapi.VMwareVCDriver, hyperv.HyperVDriver'),
     cfg.StrOpt('default_ephemeral_format',
                help='The default format an ephemeral_volume will be '
                     'formatted with on creation.'),

nova/virt/hyperv/__init__.py

@@ -0,0 +1,17 @@
+# Copyright (c) 2014 Cloudbase Solutions Srl
+#
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+from nova.virt.hyperv import driver
+
+HyperVDriver = driver.HyperVDriver