sha1_file.c: simplify parse_pack_index()

It was implemented as a thin wrapper around an otherwise unused
helper function parse_pack_index_file().  The code becomes simpler
and easier to read by consolidating the two.
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

cache.h

@@ -694,8 +694,6 @@ extern struct ref **get_remote_heads(int in, struct ref **list, int nr_match, ch
 extern int server_supports(const char *feature);
 
 extern struct packed_git *parse_pack_index(unsigned char *sha1);
-extern struct packed_git *parse_pack_index_file(const unsigned char *sha1,
-						const char *idx_path);
 
 extern void prepare_packed_git(void);
 extern void reprepare_packed_git(void);

sha1_file.c

@@ -831,13 +831,7 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 
 struct packed_git *parse_pack_index(unsigned char *sha1)
 {
-	char *path = sha1_pack_index_name(sha1);
-	return parse_pack_index_file(sha1, path);
-}
-
-struct packed_git *parse_pack_index_file(const unsigned char *sha1,
-					 const char *idx_path)
-{
+	const char *idx_path = sha1_pack_index_name(sha1);
 	const char *path = sha1_pack_name(sha1);
 	struct packed_git *p = xmalloc(sizeof(*p) + strlen(path) + 2);