fast-import: Fix uninitialized variable

Fix uninitialized last_object->no_free variable that is accessed in
store_object.
Signed-off-by: NSimon Hausmann <simon@lst.de>
Signed-off-by: NShawn O. Pearce <spearce@spearce.org>

fast-import.c

@@ -1122,6 +1122,7 @@ static void store_tree(struct tree_entry *root)
 		|| le->pack_id != pack_id) {
 		lo.data = NULL;
 		lo.depth = 0;
+		lo.no_free = 0;
 	} else {
 		mktree(t, 0, &lo.len, &old_tree);
 		lo.data = old_tree.buffer;