dl: delete blank line from codereview.cfg

It's not needed. It's not there in other subrepos:

- https://github.com/golang/image/blob/c73c2afc3b812cdd6385de5a50616511c4a3d458/codereview.cfg
- https://github.com/golang/net/blob/161cd47e91fd58ac17490ef4d742dc98bb4cf60e/codereview.cfg

Using this to test PRs for golang/go#26949.

Change-Id: I7152ea2dae1a511928e787598696274cf2b315f9
GitHub-Last-Rev: 51dbb14703592a95f599231ff29d8692ceb244d4
GitHub-Pull-Request: golang/dl#1
Reviewed-on: https://go-review.googlesource.com/134117
Reviewed-by: Andrew Bonventre <andybons@golang.org>
diff --git a/codereview.cfg b/codereview.cfg
index 19f184f..3f8b14b 100644
--- a/codereview.cfg
+++ b/codereview.cfg
@@ -1,2 +1 @@
 issuerepo: golang/go
-