status: add color config slots for branch info in "--short --branch"

Add color config slots to be used in the status short-format when
displaying local and remote tracking branch information.

[jc: rebased on top of Peff's fix to 'git status' and tweaked the
test to check both local and remote-tracking branch output]

Signed-off-by: Stephen Kent <smkent@smkent.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin/commit.c b/builtin/commit.c
index 1d805f5..9028bfa 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1263,6 +1263,10 @@ static int parse_status_slot(const char *slot)
 		return WT_STATUS_NOBRANCH;
 	if (!strcasecmp(slot, "unmerged"))
 		return WT_STATUS_UNMERGED;
+	if (!strcasecmp(slot, "localBranch"))
+		return WT_STATUS_LOCAL_BRANCH;
+	if (!strcasecmp(slot, "remoteBranch"))
+		return WT_STATUS_REMOTE_BRANCH;
 	return -1;
 }