[autotest] deploy_server fix retry message.

BUG=None
TEST=None

Change-Id: I97d10f9d70b7ea58f9c1e1d611c82444650a6c3e
Reviewed-on: https://chromium-review.googlesource.com/393306
Commit-Queue: Kevin Cheng <kevcheng@chromium.org>
Tested-by: Kevin Cheng <kevcheng@chromium.org>
Reviewed-by: Dan Shi <dshi@google.com>
diff --git a/site_utils/deploy_server.py b/site_utils/deploy_server.py
index e5fe5ea..7b26bab 100755
--- a/site_utils/deploy_server.py
+++ b/site_utils/deploy_server.py
@@ -265,7 +265,7 @@
             print('  %s' % server)
         print()
         print('To retry:')
-        print('  %s <options> %s', (args[0], ' '.join(failed + skipped)))
+        print('  %s <options> %s' % (args[0], ' '.join(failed + skipped)))
 
 
 if __name__ == '__main__':