merge-{ort,recursive}: remove add_submodule_odb()

After the parent commit and some of its ancestors, the only place
commits are being accessed through alternates is in the user-facing
message formatting code. Fix those, and remove the add_submodule_odb()
calls.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/strbuf.c b/strbuf.c
index c8a5789..b22e981 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -1059,15 +1059,21 @@ void strbuf_addftime(struct strbuf *sb, const char *fmt, const struct tm *tm,
 	strbuf_setlen(sb, sb->len + len);
 }
 
-void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
-			      int abbrev_len)
+void strbuf_repo_add_unique_abbrev(struct strbuf *sb, struct repository *repo,
+				   const struct object_id *oid, int abbrev_len)
 {
 	int r;
 	strbuf_grow(sb, GIT_MAX_HEXSZ + 1);
-	r = find_unique_abbrev_r(sb->buf + sb->len, oid, abbrev_len);
+	r = repo_find_unique_abbrev_r(repo, sb->buf + sb->len, oid, abbrev_len);
 	strbuf_setlen(sb, sb->len + r);
 }
 
+void strbuf_add_unique_abbrev(struct strbuf *sb, const struct object_id *oid,
+			      int abbrev_len)
+{
+	strbuf_repo_add_unique_abbrev(sb, the_repository, oid, abbrev_len);
+}
+
 /*
  * Returns the length of a line, without trailing spaces.
  *