[PATCH v4] branch.c: change install_branch_config() to use skip_prefix()

[Guanglin Xu <mzguanglin@gmail.com>]

to avoid a magic code of 11.

Helped-by: Sun He <sunheeh...@gmail.com>
Helped-by: Eric Sunshine <sunsh...@sunshineco.com>
Helped-by: Jacopo Notarstefano <jaco...@gmail.com>

Signed-off-by: Guanglin Xu <mzguanglin@gmail.com>
---

This is an implementation of the idea#2 of GSoC 2014 microproject.

 branch.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/branch.c b/branch.c
index 723a36b..4eec0ac 100644
--- a/branch.c
+++ b/branch.c
@@ -49,8 +49,12 @@ static int should_setup_rebase(const char *origin)
 
 void install_branch_config(int flag, const char *local, const char *origin, const char *remote)
 {
-	const char *shortname = remote + 11;
-	int remote_is_branch = starts_with(remote, "refs/heads/");
+	const char *shortname = skip_prefix(remote ,"refs/heads/");
+	int remote_is_branch;
+	if (NULL == shortname)
+		remote_is_branch = 0;
+	else
+		remote_is_branch = 1;
 	struct strbuf key = STRBUF_INIT;
 	int rebasing = should_setup_rebase(origin);
 
-- 
1.9.0