Rename Node.hold_reason to 'comment'

The nodepool ZooKeeper model already has a 'comment' field. Zuul
should just use that instead, keeping the models in sync.

Change-Id: Ia1aacc756351ba87ccb78e249e6b19e6ea86a188

tests/unit/test_scheduler.py

@@ -1470,7 +1470,7 @@ class TestScheduler(ZuulTestCase):
                       'review.example.com/org/project',
                       'project-test2'])
         )
-        self.assertEqual(held_node['hold_reason'], "reason text")
+        self.assertEqual(held_node['comment'], "reason text")
 
         # Another failed change should not hold any more nodes
         B = self.fake_gerrit.addFakeChange('org/project', 'master', 'B')

zuul/model.py

@@ -357,7 +357,7 @@ class Node(object):
         self.id = None
         self.lock = None
         self.hold_job = None
-        self.hold_reason = None
+        self.comment = None
         # Attributes from Nodepool
         self._state = 'unknown'
         self.state_time = time.time()
@@ -399,7 +399,7 @@ class Node(object):
         d = {}
         d['state'] = self.state
         d['hold_job'] = self.hold_job
-        d['hold_reason'] = self.hold_reason
+        d['comment'] = self.comment
         for k in self._keys:
             d[k] = getattr(self, k)
         return d

zuul/nodepool.py

@@ -61,7 +61,7 @@ class Nodepool(object):
         for node in nodes:
             node.state = model.STATE_HOLD
             node.hold_job = " ".join(autohold_key)
-            node.hold_reason = reason
+            node.comment = reason
             self.sched.zk.storeNode(node)
 
         # We remove the autohold when the number of nodes in hold