Adds binding for PATCH /v2/plans/:plan_uuid

Adds simplest code to PATCH existing Plan.
Adds test for success.

Change-Id: If32374ed93682e21bc5bb34a556e8d22a1340c95

tuskarclient/tests/v2/test_plans.py

@@ -57,3 +57,15 @@ class PlanManagerTest(tutils.TestCase):
         self.pm._create.assert_called_with(
             '/v2/plans',
             {'dummy': 'dummy plan data'})
+
+    def test_patch(self):
+        """Test patching a plan."""
+        self.pm._patch = mock.Mock(return_value=['fake_plan'])
+
+        self.assertEqual(
+            self.pm.patch('42', dummy='dummy plan data'),
+            ['fake_plan'])
+
+        self.pm._patch.assert_called_with(
+            '/v2/plans/42',
+            {'dummy': 'dummy plan data'})

tuskarclient/v2/plans.py

@@ -68,3 +68,17 @@ class PlanManager(base.Manager):
         :rtype: tuskarclient.v1.plans.Plan
         """
         return self._create(self._path(), fields)
+
+    def patch(self, plan_uuid, **fields):
+        """Patch an existing Plan.
+
+        :param plan_uuid: UUID of the Plan.
+        :type plan_uuid: string
+
+        :param fields: A set of key/value pairs representing the Plan.
+        :type fields: string
+
+        :return: A Plan instance or None if its not found.
+        :rtype: tuskarclient.v2.plans.Plan or None
+        """
+        return self._patch(self._single_path(plan_uuid), fields)