[PATCH v3] Place cache.h at the first place to match general rule

[Sun He <sunheehnus@gmail.com>]

 The general rule is if cache.h or git-compat-util.h is included,
 it is the first #include.
 As builtin.h starts with git-compat-util.h, files that start with builtin.h
 are not changed.

Helped-by: Duy Nguyen <pclouds@gmail.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Sun He <sunheehnus@gmail.com>
---

 "PATCH v3" fix the position of information I want to convey to readers,
 with the directions of Eric Sunshine.

 sigchain.c and test-sigchain.c are started with "sigchain.h"
 I checked sigchain.h, and it didn't import any bug.
 But to keep consistant with general rule, we should take this patch.

 sigchain.c      | 2 +-
 test-sigchain.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/sigchain.c b/sigchain.c
index 1118b99..faa375d 100644
--- a/sigchain.c
+++ b/sigchain.c
@@ -1,5 +1,5 @@
-#include "sigchain.h"
 #include "cache.h"
+#include "sigchain.h"
 
 #define SIGCHAIN_MAX_SIGNALS 32
 
diff --git a/test-sigchain.c b/test-sigchain.c
index 42db234..e499fce 100644
--- a/test-sigchain.c
+++ b/test-sigchain.c
@@ -1,5 +1,5 @@
-#include "sigchain.h"
 #include "cache.h"
+#include "sigchain.h"
 
 #define X(f) \
 static void f(int sig) { \
-- 
1.9.0.138.g2de3478.dirty