branch: use skip_prefix() in install_branch_config()

The install_branch_config() function reimplemented the skip_prefix()
function inline.

Reported-by: Michael Haggerty <[email protected]>
Signed-off-by: Brian Gesiak <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

branch.c

@@ -1,3 +1,4 @@
+#include "git-compat-util.h"
 #include "cache.h"
 #include "branch.h"
 #include "refs.h"
@@ -49,12 +50,11 @@ 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/");
 	struct strbuf key = STRBUF_INIT;
 	int rebasing = should_setup_rebase(origin);
 
-	if (remote_is_branch
+	if (shortname
 	    && !strcmp(local, shortname)
 	    && !origin) {
 		warning(_("Not setting branch %s as its own upstream."),
@@ -77,29 +77,29 @@ void install_branch_config(int flag, const char *local, const char *origin, cons
 	strbuf_release(&key);
 
 	if (flag & BRANCH_CONFIG_VERBOSE) {
-		if (remote_is_branch && origin)
+		if (shortname && origin)
 			printf_ln(rebasing ?
 				  _("Branch %s set up to track remote branch %s from %s by rebasing.") :
 				  _("Branch %s set up to track remote branch %s from %s."),
 				  local, shortname, origin);
-		else if (remote_is_branch && !origin)
+		else if (shortname && !origin)
 			printf_ln(rebasing ?
 				  _("Branch %s set up to track local branch %s by rebasing.") :
 				  _("Branch %s set up to track local branch %s."),
 				  local, shortname);
-		else if (!remote_is_branch && origin)
+		else if (!shortname && origin)
 			printf_ln(rebasing ?
 				  _("Branch %s set up to track remote ref %s by rebasing.") :
 				  _("Branch %s set up to track remote ref %s."),
 				  local, remote);
-		else if (!remote_is_branch && !origin)
+		else if (!shortname && !origin)
 			printf_ln(rebasing ?
 				  _("Branch %s set up to track local ref %s by rebasing.") :
 				  _("Branch %s set up to track local ref %s."),
 				  local, remote);
 		else
-			die("BUG: impossible combination of %d and %p",
-			    remote_is_branch, origin);
+			die("BUG: impossible combination of %p and %p",
+			    shortname, origin);
 	}
 }