If redo searched all the way up to /default.do, it would run ./default.do instead.

This only happened if the containing project was buggy, ie. you tried
to build a target that has no .do file available anywhere. However, it
resulted in a confusing outcome for that case, where we'd run the wrong
default.do file with the wrong parameters.

Extended an existing test to catch this mistake.

redo/builder.py

@@ -183,6 +183,8 @@ class _BuildJob(object):
                 return self._finalize(0)
             else:
                 err('no rule to redo %r\n' % t)
+                sf.set_failed()
+                sf.save()
                 return self._finalize(1)
         # There is no good place for us to pre-create a temp file for
         # stdout.  The target dir might not exist yet, or it might currently