buffet: Sorted headers alphabetically (build/include_alpha)

We are going to enable build/include_alpha linter warning soon,
so in preparation for this, fixed the warnings in buffet.

BUG=None
TEST=cpplint.py --filter=-build/include_order,+build/include_alpha buffet/* buffet/commands/*

Change-Id: I103670d12f1eaec552d2ff21017316bb41b16b78
Reviewed-on: https://chromium-review.googlesource.com/209562
Tested-by: Alex Vakulenko <avakulenko@chromium.org>
Reviewed-by: Chris Sosa <sosa@chromium.org>
Reviewed-by: Christopher Wiley <wiley@chromium.org>
Commit-Queue: Alex Vakulenko <avakulenko@chromium.org>
diff --git a/buffet/http_request.h b/buffet/http_request.h
index e5b9710..9bb436e 100644
--- a/buffet/http_request.h
+++ b/buffet/http_request.h
@@ -14,9 +14,9 @@
 
 #include <base/basictypes.h>
 
+#include "buffet/error.h"
 #include "buffet/http_connection.h"
 #include "buffet/http_transport.h"
-#include "buffet/error.h"
 
 namespace buffet {
 namespace http {