Code review comment for lp:~roadmr/isitdeployable/revision-disappeared-ohnoes

Do I need to put code in markup to prevent whitespace mangling? Apologies for experimenting on your MP.

```
  tip_revision = self.tip_revision()
  if (start_revision is not None and
+ tip_revision is not None and
      tip_revision.revno <= start_revision.revno):
          return
```