pack-objects: introduce pack.allowPackReuse

Let's make it possible to configure if we want pack reuse or not.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/pack-objects.c

@@ -96,6 +96,7 @@ static off_t reuse_packfile_offset;
 
 static int use_bitmap_index_default = 1;
 static int use_bitmap_index = -1;
+static int allow_pack_reuse = 1;
 static enum {
 	WRITE_BITMAP_FALSE = 0,
 	WRITE_BITMAP_QUIET,
@@ -2719,6 +2720,10 @@ static int git_pack_config(const char *k, const char *v, void *cb)
 		sparse = git_config_bool(k, v);
 		return 0;
 	}
+	if (!strcmp(k, "pack.allowpackreuse")) {
+		allow_pack_reuse = git_config_bool(k, v);
+		return 0;
+	}
 	if (!strcmp(k, "pack.threads")) {
 		delta_search_threads = git_config_int(k, v);
 		if (delta_search_threads < 0)
@@ -3063,7 +3068,8 @@ static int get_object_list_from_bitmap(struct rev_info *revs)
 	if (!(bitmap_git = prepare_bitmap_walk(revs)))
 		return -1;
 
-	if (pack_options_allow_reuse() &&
+	if (allow_pack_reuse &&
+	    pack_options_allow_reuse() &&
 	    !reuse_partial_packfile_from_bitmap(
 			bitmap_git,
 			&reuse_packfile,