merge_trees(): ensure that the callers release output buffer

diff --git a/t/t7508-status.sh b/t/t7508-status.sh
index b3bdd162aaaf0fed0be9f62feab6aeb4b7019dbe..fb00e6d9b07f4cc6f478bb532749403017599400 100755 (executable)
--- a/t/t7508-status.sh
+++ b/t/t7508-status.sh
@@ -803,7 +803,7 @@ EOF
 '
 
 cat >expect <<EOF
-:100644 100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 0000000000000000000000000000000000000000 M     dir1/modified
+:100644 100644 $EMPTY_BLOB 0000000000000000000000000000000000000000 M  dir1/modified
 EOF
 test_expect_success 'status refreshes the index' '
        touch dir2/added &&