sha1_file.c: Avoid multiple calls to find_pack_entry().

We used to call find_pack_entry() twice from read_sha1_file() in order
to avoid printing an error message, when the object did not exist.  This
is fixed by moving the call to error() to the only place it really
could be called.
Signed-off-by: NPeter Eriksen <s022018@student.dtu.dk>
Signed-off-by: NJunio C Hamano <junkio@cox.net>

sha1_file.c

@@ -1469,21 +1469,20 @@ static void *read_packed_sha1(const unsigned char *sha1, char *type, unsigned lo
 {
 	struct pack_entry e;
 
-	if (!find_pack_entry(sha1, &e, NULL)) {
-		error("cannot read sha1_file for %s", sha1_to_hex(sha1));
+	if (!find_pack_entry(sha1, &e, NULL))
 		return NULL;
-	}
-	return unpack_entry(e.p, e.offset, type, size);
+	else
+		return unpack_entry(e.p, e.offset, type, size);
 }
 
 void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size)
 {
 	unsigned long mapsize;
 	void *map, *buf;
-	struct pack_entry e;
 
-	if (find_pack_entry(sha1, &e, NULL))
-		return read_packed_sha1(sha1, type, size);
+	buf = read_packed_sha1(sha1, type, size);
+	if (buf)
+		return buf;
 	map = map_sha1_file(sha1, &mapsize);
 	if (map) {
 		buf = unpack_sha1_file(map, mapsize, type, size);
@@ -1491,9 +1490,7 @@ void * read_sha1_file(const unsigned char *sha1, char *type, unsigned long *size
 		return buf;
 	}
 	reprepare_packed_git();
-	if (find_pack_entry(sha1, &e, NULL))
-		return read_packed_sha1(sha1, type, size);
-	return NULL;
+	return read_packed_sha1(sha1, type, size);
 }
 
 void *read_object_with_reference(const unsigned char *sha1,
@@ -1781,6 +1778,8 @@ static void *repack_object(const unsigned char *sha1, unsigned long *objsize)
 
 	/* need to unpack and recompress it by itself */
 	unpacked = read_packed_sha1(sha1, type, &len);
+	if (!unpacked)
+		error("cannot read sha1_file for %s", sha1_to_hex(sha1));
 
 	hdrlen = sprintf(hdr, "%s %lu", type, len) + 1;