cache-tree: avoid an unnecessary check

The first thing the `parse_tree()` function does is to return early if
the tree has already been parsed. Therefore we do not need to guard the
`parse_tree()` call behind a check of that flag.

As of time of writing, there are no other instances of this in Git's
code bases: whenever the `parsed` flag guards a `parse_tree()` call, it
guards more than just that call.

Suggested-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

cache-tree.c

@@ -779,7 +779,7 @@ static void prime_cache_tree_rec(struct repository *r,
 			struct cache_tree_sub *sub;
 			struct tree *subtree = lookup_tree(r, &entry.oid);
 
-			if (!subtree->object.parsed && parse_tree(subtree) < 0)
+			if (parse_tree(subtree) < 0)
 				exit(128);
 			sub = cache_tree_sub(it, entry.path);
 			sub->cache_tree = cache_tree();