name-rev: fix parent counting.

Noticed by linux@horizon.com.  The first merge parent (typically
"our branch") is ^1, not ^0, and the first other branch is ^2.
Signed-off-by: NJunio C Hamano <junkio@cox.net>

name-rev.c

@@ -21,7 +21,7 @@ static void name_rev(struct commit *commit,
 {
 	struct rev_name *name = (struct rev_name *)commit->object.util;
 	struct commit_list *parents;
-	int parent_number = 0;
+	int parent_number = 1;
 
 	if (!commit->object.parsed)
 		parse_commit(commit);
@@ -56,7 +56,7 @@ static void name_rev(struct commit *commit,
 	for (parents = commit->parents;
 			parents;
 			parents = parents->next, parent_number++) {
-		if (parent_number > 0) {
+		if (parent_number > 1) {
 			char *new_name = xmalloc(strlen(tip_name)+8);
 
 			if (generation > 0)