cache-tree tests: remove unused $2 parameter

Remove the $2 paramater. This appears to have been some
work-in-progress code from an earlier version of
9c4d6c0297 (cache-tree: Write updated cache-tree after commit,
2014-07-13) which was left in the final version.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t0090-cache-tree.sh

@@ -19,7 +19,6 @@ cmp_cache_tree () {
 # correct.
 generate_expected_cache_tree_rec () {
 	dir="$1${1:+/}" &&
-	parent="$2" &&
 	# ls-files might have foo/bar, foo/bar/baz, and foo/bar/quux
 	# We want to count only foo because it's the only direct child
 	git ls-files >files &&
@@ -30,10 +29,9 @@ generate_expected_cache_tree_rec () {
 	for subtree in $subtrees
 	do
 		cd "$subtree"
-		generate_expected_cache_tree_rec "$dir$subtree" "$dir" || return 1
+		generate_expected_cache_tree_rec "$dir$subtree" || return 1
 		cd ..
-	done &&
-	dir=$parent
+	done
 }
 
 generate_expected_cache_tree () {