cleanups: ensure that git-compat-util.h is included first

CodingGuidelines states that the first #include in C files should be
git-compat-util.h or another header file that includes it, such as
cache.h or builtin.h.

Signed-off-by: David Aguilar <davvid@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

merge-recursive.c

@@ -3,8 +3,8 @@
  * Fredrik Kuivinen.
  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
  */
-#include "advice.h"
 #include "cache.h"
+#include "advice.h"
 #include "cache-tree.h"
 #include "commit.h"
 #include "blob.h"