cache_or_unpack_entry: drop keep_cache parameter

There is only one caller of cache_or_unpack_entry() and it
always passes 1 for the keep_cache parameter. We can
simplify it by dropping the "!keep_cache" case.

Another call, which did pass 0, was dropped in abe601b
(sha1_file: remove recursion in unpack_entry, 2013-03-27),
as unpack_entry() now does more complicated things than a
simple unpack when there is a cache miss.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

sha1_file.c

@@ -2129,25 +2129,18 @@ static void clear_delta_base_cache_entry(struct delta_base_cache_entry *ent)
 }
 
 static void *cache_or_unpack_entry(struct packed_git *p, off_t base_offset,
-	unsigned long *base_size, enum object_type *type, int keep_cache)
+	unsigned long *base_size, enum object_type *type)
 {
 	struct delta_base_cache_entry *ent;
-	void *ret;
 
 	ent = get_delta_base_cache_entry(p, base_offset);
 
 	if (!eq_delta_base_cache_entry(ent, p, base_offset))
 		return unpack_entry(p, base_offset, type, base_size);
 
-	ret = ent->data;
-
-	if (!keep_cache)
-		clear_delta_base_cache_entry(ent);
-	else
-		ret = xmemdupz(ent->data, ent->size);
 	*type = ent->type;
 	*base_size = ent->size;
-	return ret;
+	return xmemdupz(ent->data, ent->size);
 }
 
 static inline void release_delta_base_cache(struct delta_base_cache_entry *ent)
@@ -2755,7 +2748,7 @@ static void *read_packed_sha1(const unsigned char *sha1,
 
 	if (!find_pack_entry(sha1, &e))
 		return NULL;
-	data = cache_or_unpack_entry(e.p, e.offset, size, type, 1);
+	data = cache_or_unpack_entry(e.p, e.offset, size, type);
 	if (!data) {
 		/*
 		 * We're probably in deep shit, but let's try to fetch