Merge branch 'nd/misc-cleanups'

* nd/misc-cleanups: unpack_object_header_buffer(): clear the size field upon error tree_entry_interesting: make use of local pointer "item" tree_entry_interesting(): give meaningful names to return values read_directory_recursive: reduce one indentation level get_tree_entry(): do not call find_tree_entry() on an empty tree tree-walk.c: do not leak internal structure in tree_entry_len()