unpack_trees(): start with a fresh lstat cache

We really want to avoid relying on stale information.

Signed-off-by: Matheus Tavares <matheus.bernardino@usp.br>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
diff --git a/unpack-trees.c b/unpack-trees.c
index 88a0b5d..5914e7b 100644
--- a/unpack-trees.c
+++ b/unpack-trees.c
@@ -349,6 +349,9 @@
 
 	progress = get_progress(o);
 
+	/* Start with clean cache to avoid using any possibly outdated info. */
+	invalidate_lstat_cache();
+
 	if (o->update)
 		git_attr_set_direction(GIT_ATTR_CHECKOUT, index);