Define reviewers outside of conditional scope.

Fixes bug where reviewers isn't set properly.

BUG=chromium-os:37852
TEST=Ran it/pylint

Change-Id: I275d3e3eeeb11caee7d7b78507c7a9478547f6c9
Reviewed-on: https://gerrit.chromium.org/gerrit/41222
Tested-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
Commit-Queue: Chris Sosa <sosa@chromium.org>
diff --git a/scripts/cros_merge_to_branch.py b/scripts/cros_merge_to_branch.py
index d974eb7..4ecc120 100644
--- a/scripts/cros_merge_to_branch.py
+++ b/scripts/cros_merge_to_branch.py
@@ -94,11 +94,11 @@
 
   # Get the new sha1 after apply.
   new_sha1 = git.GetGitRepoRevision(work_dir)
+  reviewers = set()
 
   # If the sha1 has changed, then rewrite the commit message.
   if patch.sha1 != new_sha1:
     msg = []
-    reviewers = set()
     for line in patch.commit_message.splitlines():
       if line.startswith('Reviewed-on: '):
         line = 'Previous-' + line