Merge branch 'jh/status-no-ahead-behind'

"git status" can spend a lot of cycles to compute the relation
between the current branch and its upstream, which can now be
disabled with "--no-ahead-behind" option.

* jh/status-no-ahead-behind:
  status: support --no-ahead-behind in long format
  status: update short status to respect --no-ahead-behind
  status: add --[no-]ahead-behind to status and commit for V2 format.
  stat_tracking_info: return +1 when branches not equal

builtin/checkout.c

@@ -609,7 +609,7 @@ static void report_tracking(struct branch_info *new_branch_info)
 	struct strbuf sb = STRBUF_INIT;
 	struct branch *branch = branch_get(new_branch_info->name);
 
-	if (!format_tracking_info(branch, &sb))
+	if (!format_tracking_info(branch, &sb, AHEAD_BEHIND_FULL))
 		return;
 	fputs(sb.buf, stdout);
 	strbuf_release(&sb);