Add revision for drive resource

Adds ``Revision`` property to the ``Drive`` resource.

Change-Id: Ife9e09994fc74393e551ad5cd6ab362ba890e126
Signed-off-by: Manuel Schönlaub <manuel.schoenlaub@gmail.com>

releasenotes/notes/add-drive-revision-a0c069fff236479d.yaml

@@ -0,0 +1,4 @@
+---
+features:
+  - |
+    Adds the ``Revision`` property to the ``Drive`` resource.

sushy/resources/system/storage/drive.py

@@ -62,6 +62,9 @@ class Drive(base.ResourceBase):
     protocol = base.MappedField('Protocol', res_maps.PROTOCOL_TYPE_VALUE_MAP)
     """Protocol this drive is using to communicate to the storage controller"""
 
+    revision = base.Field("Revision")
+    """The firmware/hardware version of the drive."""
+
     serial_number = base.Field('SerialNumber')
     """The serial number for this drive"""
 

sushy/tests/unit/resources/system/storage/test_drive.py

@@ -55,6 +55,7 @@ class DriveTestCase(base.TestCase):
         self.assertEqual('C123-1111', self.stor_drive.part_number)
         self.assertEqual(sushy.PROTOCOL_TYPE_SAS, self.stor_drive.protocol)
         self.assertEqual('1234570', self.stor_drive.serial_number)
+        self.assertEqual('100A', self.stor_drive.revision)
         self.assertEqual(sushy.STATE_ENABLED, self.stor_drive.status.state)
         self.assertEqual(sushy.HEALTH_OK, self.stor_drive.status.health)