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/commands/command_manager.cc b/buffet/commands/command_manager.cc
index 48a323f..26c0b9f 100644
--- a/buffet/commands/command_manager.cc
+++ b/buffet/commands/command_manager.cc
@@ -6,10 +6,10 @@
 
 #include <base/at_exit.h>
 #include <base/bind.h>
-#include <base/files/file_enumerator.h>
 #include <base/file_util.h>
-#include <base/values.h>
+#include <base/files/file_enumerator.h>
 #include <base/json/json_reader.h>
+#include <base/values.h>
 
 #include "buffet/commands/schema_constants.h"
 #include "buffet/error_codes.h"