Merge pull request #4123 from apache/dev-run-fix-haproxy-cfg

make haproxy config valid again
diff --git a/dev/run b/dev/run
index e030967..f877860 100755
--- a/dev/run
+++ b/dev/run
@@ -351,6 +351,7 @@
 
     with open(haproxy_config, "w") as handle:
         handle.write("\n".join(out))
+        handle.write("\n")
 
 
 def apply_config_overrides(ctx, content):