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>

http.c

@@ -1,3 +1,4 @@
+#include "git-compat-util.h"
 #include "http.h"
 #include "pack.h"
 #include "sideband.h"